The ATP Challenger Series is the second tier tour for professional tennis organised by the Association of Tennis Professionals (ATP). The 1998 ATP Challenger Series calendar comprised 114 tournaments, with prize money ranging from $25,000 up to $125,000.^[1][2]

Date	Country	Tournament	Prizemoney	Surface	Singles champion	Doubles champions
26.01.	Germany	Heilbronn Open	$ 100,000	Carpet (i)	Martin Sinner	Geoff Grant Mark Merklein

Date	Country	Tournament	Prizemoney	Surface	Singles champion	Doubles champions
02.02.	South Africa	West Bloomfield Challenger	$ 050,000	Hard (i)	Alex O'Brien	Jim Thomas Laurence Tieleman
	Germany	Lippstadt Challenger	$ 025,000	Carpet (i)	Dirk Dier	Andrew Richardson Myles Wakefield
09.02.	Germany	Volkswagen Challenger	$ 025,000	Carpet (i)	Ivo Heuberger	Marat Safin Dušan Vemić
16.02.	Singapore	Singapore Challenger	$ 050,000	Hard	Fernando Vicente	Jim Thomas Laurence Tieleman
	Germany	Warsteiner Challenger Lübeck	$ 025,000	Carpet (i)	Peter Wessels	Lorenzo Manta Andrew Richardson
23.02.	Vietnam	Ho Chi Minh Challenger	$ 050,000	Hard	André Sá	Mahesh Bhupathi Peter Tramacchi
	France	Cherbourg Challenger	$ 025,000	Hard (i)	Jérôme Golmard	Massimo Ardinghi Massimo Bertolini

Date	Country	Tournament	Prizemoney	Surface	Singles champion	Doubles champions
02.03.	Thailand	Bangkok Challenger	$ 050,000	Hard	Leander Paes	Peter Tramacchi Kevin Ullyett
	Germany	Residenza Open Magdeburg	$ 025,000	Carpet (i)	Lars Burgsmüller	Eyal Erlich Mosé Navarra
09.03.	Ecuador	Salinas Challenger	$ 050,000	Hard	André Sá	David DiLucia Michael Sell
	Japan	Kyoto Challenger	$ 025,000	Carpet (i)	Michael Kohlmann	Takao Suzuki Kevin Ullyett
30.03.	Italy	Barletta Challenger	$ 025,000	Clay	Francisco Cabello	Joan Balcells Juan Ignacio Carrasco

Date	Country	Tournament	Prizemoney	Surface	Singles champion	Doubles champions
06.04.	Bermuda	XL Bermuda Open	$ 100,000	Clay	Hernán Gumy	Doug Flach Richey Reneberg
	Italy	Napoli Challenger	$ 100,000	Clay	Davide Sanguinetti	Massimo Bertolini Devin Bowen
	Mexico	San Luis Potosí Challenger	$ 025,000	Clay	Luis Morejón	Edwin Kempes Peter Wessels
13.04.	France	Nice Challenger	$ 100,000	Clay	Mariano Puerta	Devin Bowen Mariano Hood
	United States	Birmingham Challenger	$ 050,000	Clay	Christian Ruud	Doug Flach David Witt
	India	Vadodara Challenger	$ 050,000	Grass	Peter Tramacchi	Myles Wakefield Wesley Whitehouse
	Mexico	Puerto Vallarta Challenger	$ 025,000	Hard (i)	Geoff Grant	Luis Herrera Gabriel Trifu
20.04.	Portugal	Espinho Challenger	$ 125,000	Clay	Guillermo Cañas	Jens Knippschild Stephen Noteboom
	Czech Republic	Prague Challenger	$ 025,000	Clay	Michal Tabara	Joan Balcells Nenad Zimonjić

Date	Country	Tournament	Prizemoney	Surface	Singles champion	Doubles champions
04.05.	Slovenia	Ljubljana Challenger	$ 125,000	Clay	Dinu Pescariu	Marius Barnard Stephen Noteboom
	Israel	Jerusalem Challenger	$ 050,000	Hard	Neville Godwin	Noam Behr Eyal Erlich
11.05.	Czech Republic	Košice Challenger	$ 125,000	Clay	Dominik Hrbatý	Jiří Novák David Rikl
	Germany	Ostdeutscher Sparkassen Cup	$ 050,000	Clay	Dirk Dier	Pablo Albano Sander Groen
18.05.	Hungary	Budapest Challenger I	$ 050,000	Clay	Marcos Ondruska	Chris Haggard Paul Rosner
25.05.	Ukraine	Kyiv Challenger	$ 050,000	Clay	Nenad Zimonjić	Thomas Buchmayer Thomas Strengberger
	Colombia	Medellín Challenger	$ 025,000	Clay	Adriano Ferreira	Adriano Ferreira Cristiano Testa

Date	Country	Tournament	Prizemoney	Surface	Singles champion	Doubles champions
01.06.	Czech Republic	Prostějov Challenger	$ 125,000	Clay	Richard Fromberg	Edwin Kempes Peter Wessels
	Germany	Quelle Cup	$ 050,000	Clay	Christian Ruud	Álex López Morón Albert Portas
	Great Britain	Surbiton Challenger	$ 050,000	Grass	Gianluca Pozzi	Sandon Stolle Peter Tramacchi
08.06.	Croatia	Split Challenger	$ 100,000	Clay	Orlin Stanoytchev	Geoff Grant Attila Sávolt
	Germany	ATU Cup	$ 025,000	Clay	Agustín Calleri	Nuno Marques Nenad Zimonjić
15.06.	Germany	Nord/LB Open	$ 125,000	Clay	Franco Squillari	Tomás Carbonell Francisco Roig
	Croatia	Zagreb Challenger	$ 100,000	Clay	Jiří Novák	Julián Alonso Mariano Puerta
22.06.	Italy	Biella Challenger	$ 025,000	Clay	Andrew Ilie	Diego del Río Eric Taino
	Germany	Wartburg Open	$ 025,000	Clay	Edwin Kempes	Jaime Oncins Cristiano Testa
	Czech Republic	Příbram Challenger	$ 025,000	Clay	Arnaud Di Pasquale	Ota Fukárek Udo Plamberger
29.06.	Italy	Venice Challenger	$ 100,000	Clay	Adrian Voinea	Nebojša Đorđević Marcos Ondruska
	United States	Denver Challenger	$ 050,000	Hard	Takao Suzuki	Michael Hill Glenn Weiner
	Germany	Müller Cup	$ 050,000	Clay	Younes El Aynaoui	Márcio Carlsson Jaime Oncins
	France	Montauban Challenger	$ 025,000	Clay	Edwin Kempes	Eduardo Nicolás Germán Puentes

Date	Country	Tournament	Prizemoney	Surface	Singles champion	Doubles champions
06.07.	Belgium	Ostend Challenger	$ 075,000	Clay	Andrew Ilie	Cristian Brandi Filippo Messori
	Great Britain	Bristol Challenger	$ 050,000	Grass	Denis van Uffelen	Max Mirnyi Vladimir Voltchkov
	Canada	Granby Challenger	$ 050,000	Hard	Takao Suzuki	Gouichi Motomura Takao Suzuki
	Germany	Oberstaufen Cup	$ 025,000	Clay	Wolfgang Schranz	Nuno Marques Rogier Wassen
13.07.	Italy	Merano Challenger	$ 125,000	Clay	Ctislav Doseděl	Pablo Albano Nicolás Lapentti
	United States	Aptos Challenger	$ 050,000	Hard	Cecil Mamiit	Bob Bryan Mike Bryan
	France	Contrexéville Challenger	$ 050,000	Clay	Younes El Aynaoui	Diego del Río Martín Rodríguez
	Great Britain	Manchester Challenger	$ 050,000	Grass	Chris Wilkinson	Mosé Navarra Stefano Pescosolido
20.07.	Great Britain	Newcastle Challenger	$ 050,000	Clay	Agustín Calleri	Jeff Coetzee Edwin Kempes
	Finland	Tampere Challenger	$ 050,000	Clay	Tomáš Zíb	Tobias Hildebrand Fredrik Lovén
27.07.	Turkey	Istanbul Challenger	$ 050,000	Hard	Tomáš Zíb	Petr Luxa Eyal Ran
	Netherlands	Scheveningen Challenger	$ 050,000	Clay	Younes El Aynaoui	Agustín Calleri Tobias Hildebrand
	United States	Winnetka Challenger	$ 050,000	Hard	Geoff Grant	Grant Silcock Myles Wakefield

Date	Country	Tournament	Prizemoney	Surface	Singles champion	Doubles champions
03.08.	Poland	Poznań Challenger	$ 125,000	Clay	Christian Ruud	Sebastián Prieto Martín Rodríguez
	Spain	Open Castilla y León	$ 100,000	Hard	Radek Štěpánek	Radek Štěpánek Tomáš Zíb
	United States	Lexington Challenger	$ 050,000	Hard	Paul Goldstein	Ben Ellwood Lleyton Hewitt
	Brazil	Gramado Challenger	$ 025,000	Hard	André Sá	Jeff Coetzee Damien Roberts
	Mexico	Tijuana Challenger	$ 025,000	Hard	Michael Hill	Michael Hill Scott Humphries
10.08.	United States	Binghamton Challenger	$ 050,000	Hard	Takao Suzuki	Myles Wakefield Wesley Whitehouse
	Brazil	Belo Horizonte Challenger	$ 025,000	Hard	Francisco Costa	Satoshi Iwabuchi Thomas Shimada
	Austria	Nettingsdorf Challenger	$ 025,000	Clay	Markus Hipfl	Tomáš Krupa Borut Urh
	Poland	Sopot Challenger	$ 025,000	Clay	Michał Chmela	James Greenhalgh Nenad Zimonjić
17.08.	Austria	Graz Challenger	$ 100,000	Clay	Carlos Costa	Dinu Pescariu Albert Portas
	United States	Bronx Challenger	$ 050,000	Hard	Miles Maclagan	Jared Palmer Takao Suzuki
	Poland	Warsaw Challenger	$ 050,000	Clay	Jiří Vaněk	James Greenhalgh Nenad Zimonjić
24.08.	Switzerland	Geneva Challenger	$ 050,000	Clay	Juan Albert Viloca	Rikard Bergh Jens Knippschild
31.08.	Austria	Alpirsbach Challenger	$ 025,000	Clay	Stefan Koubek	Tomáš Cibulec Leoš Friedl
	Serbia	Belgrade Challenger	$ 025,000	Hard	Jiří Vaněk	Raemon Sluiter Nenad Zimonjić
	Bolivia	Santa Cruz Challenger	$ 025,000	Clay	Gastón Gaudio	Marcelo Charpentier Andrés Schneiter

Date	Country	Tournament	Prizemoney	Surface	Singles champion	Doubles champions
07.09.	Romania	Brașov Challenger	$ 050,000	Clay	Dinu Pescariu	Juan Ignacio Carrasco Jairo Velasco Jr.
	Great Britain	Edinburgh Challenger	$ 050,000	Clay	Tomas Nydahl	Edwin Kempes Peter Wessels
	Ecuador	Quito Challenger	$ 050,000	Clay	Nicolás Massú	Adriano Ferreira Óscar Ortiz
	Yugoslavia	Budva Challenger	$ 025,000	Clay	Tomas Behrend	Eduardo Nicolás Germán Puentes
14.09.	Brazil	Florianópolis Challenger	$ 125,000	Clay	Guillermo Cañas	Jaime Oncins André Sá
	Hungary	Budapest Challenger II	$ 050,000	Clay	Renzo Furlan	Gábor Köves Thomas Strengberger
	North Macedonia	Skopje Challenger	$ 025,000	Clay	Jordi Mas	Eduardo Nicolás Germán Puentes
21.09.	Poland	Szczecin Challenger	$ 125,000	Clay	Younes El Aynaoui	Orlin Stanoytchev Radomír Vašek
	United States	Urbana Challenger	$ 025,000	Hard	Daniel Nestor	Jared Palmer Jonathan Stark
	Spain	Copa Sevilla	$ 025,000	Clay	Alberto Martín	Alberto Martín Salvador Navarro
28.09.	Portugal	Oporto Challenger	$ 125,000	Clay	Younes El Aynaoui	Juan Ignacio Carrasco Jairo Velasco Jr.
	Venezuela	Caracas Challenger	$ 100,000	Hard	Adriano Ferreira	Geoff Grant Maurice Ruah
	United States	Dallas Challenger	$ 050,000	Hard	Daniel Nestor	Jared Palmer Jonathan Stark
	Italy	Olbia Challenger	$ 050,000	Hard	Daniele Bracciali	Todd Larkham Chris Wilkinson

Date	Country	Tournament	Prizemoney	Surface	Singles champion	Doubles champions
05.10.	Chile	Santiago Challenger	$ 100,000	Clay	Sebastián Prieto	Ota Fukárek Attila Sávolt
	United States	San Antonio Challenger	$ 050,000	Hard	Geoff Grant	David DiLucia Michael Sell
	Israel	Tel Aviv Challenger	$ 050,000	Hard	Gianluca Pozzi	Radek Štěpánek Michal Tabara
12.10.	Spain	Barcelona Challenger	$ 100,000	Clay	Fernando Vicente	José Antonio Conde Javier Sánchez
	Brazil	São Paulo Challenger	$ 100,000	Clay	Fernando Meligeni	Diego del Río Martín Rodríguez
	United States	San Diego Challenger	$ 050,000	Hard	Ville Liukko	Paul Goldstein Adam Peterson
19.10.	Egypt	Cairo Challenger	$ 100,000	Clay	Albert Portas	Albert Portas Álex López Morón
	Uruguay	Montevideo Challenger	$ 100,000	Clay	Eduardo Medica	Francisco Cabello Agustín Calleri
	Hong Kong	Hongkong Challenger	$ 050,000	Hard	Not completed
	Germany	Okal Cup	$ 025,000	Carpet (i)	Jared Palmer	Tomáš Cibulec Raemon Sluiter
	Uzbekistan	Samarkand Challenger	$ 025,000	Clay	Fredrik Jonsson	Noam Behr Eyal Ran
26.10.	France	Brest Challenger	$ 100,000	Hard (i)	Jérôme Golmard	Neville Godwin Marcos Ondruska

Date	Country	Tournament	Prizemoney	Surface	Singles champion	Doubles champions
02.11.	Germany	Lambertz Open by STAWAG	$ 050,000	Hard (i)	Hendrik Dreekmann	Menno Oosting Pavel Vízner
09.11.	United States	Las Vegas Challenger	$ 050,000	Hard	Cecil Mamiit	Marcos Ondruska Byron Talbot
16.11.	Andorra	Andorra Challenger	$ 100,000	Hard (i)	Justin Gimelstob	Justin Gimelstob Jack Waite
	Argentina	Buenos Aires Challenger	$ 100,000	Clay	Younes El Aynaoui	Guillermo Cañas Martín García
	Mexico	Puebla Challenger	$ 025,000	Hard	Vladimir Voltchkov	Alejandro González Mariano Sánchez
	United States	Rancho Mirage Challenger	$ 025,000	Hard	Christian Ruud	Wayne Arthurs Peter Tramacchi
23.11.	Peru	Lima Challenger	$ 100,000	Clay	Stefan Koubek	Diego del Río Martin Rodriguez
	United States	Burbank Challenger	$ 025,000	Hard	Cecil Mamiit	Mike Bryan Mike Bryan
	Slovenia	Portorož Challenger	$ 025,000	Hard (i)	Rainer Schüttler	Max Mirnyi Andrei Olhovskiy
	Mexico	Toluca Challenger	$ 025,000	Clay	Rogier Wassen	Alejandro Hernández Mariano Sánchez
30.11.	Mexico	Guadalajara Challenger	$ 100,000	Clay	Markus Hipfl	Sander Groen Ali Hamadeh
	Germany	Nümbrecht Challenger	$ 050,000	Carpet (i)	Christian Vinck	Max Mirnyi Andrei Olhovskiy

Date	Country	Tournament	Prizemoney	Surface	Singles champion	Doubles champions
07.12.	Australia	Perth Challenger	$ 025,000	Hard	Lleyton Hewitt	Lleyton Hewitt Paul Kilderry
	Chile	Cerveza Cristal	$ 025,000	Clay	Gastón Gaudio	Enzo Artoni Federico Browne
21.12.	India	Ahmedabad Challenger	$ 025,000	Hard	Antony Dupuis	Noam Okun Nir Welgreen
28.12.	India	Mumbai Challenger	$ 025,000	Hard	Antony Dupuis	Noam Behr Eyal Ran