Communist Party of Slovakia Komunistická strana Slovenska
Founded	May 1939
Dissolved	22 November 1990
Preceded by	Communist Party of Czechoslovakia
Succeeded by	Party of the Democratic Left
Newspaper	Pravda
Ideology	Communism Marxism–Leninism Stalinism (until 1956)
Political position	Far-left
National affiliation	Communist Party of Czechoslovakia (1948–1990)
National organization	National Front (1944–1990)
Politics of Slovakia Political parties Elections Politics of Czechoslovakia Political parties Elections

The Communist Party of Slovakia (Slovak: Komunistická strana Slovenska, KSS) was a communist party in Slovakia. It was formed in May 1939, when the Slovak Republic was created, as the Slovak branches of the Communist Party of Czechoslovakia (KSČ) were separated from the mother party. When Czechoslovakia was again established as a unified state, the KSS was still a separate party for a while (1945–1948). On 29 September 1948, it was reunited with the KSČ and continued to exist as an "organizational territorial unit of the KSČ on the territory of Slovakia". Its main organ (and thus the main newspaper in Slovakia at the time) was Pravda.

After the merger KSS functioned as a regional affiliate of the KSČ, not as an independent political institution. Therefore, the organizational structure of the KSS mirrored that of the KSČ: the KSS Congress held session for several days every five years (and just before the KSČ's Congress), selecting its Central Committee members and candidate members, who in turn selected a Presidium, a Secretariat, and a First Secretary (i.e. party leader).

The most important first secretaries were Alexander Dubček (1963–1968) and Jozef Lenárt (1970–1988). Following the March 1986 party congress, the KSS Presidium consisted of 11 members; the Secretariat included, in addition to Lenárt, three secretaries and two members; and the Central Committee comprised 95 full members and 36 candidate members. The KSS in 1986 also had its own Central Control and Auditing Commission, four other commissions, twelve party departments, and one training facility.

KSS ceased to exist in 1990 (following the Velvet Revolution), when it was transformed into the independent social democratic party called the Party of Democratic Left (SDĽ). Most of that party, in turn, is now part of Direction – Social Democracy, which had separated from the SDĽ in 2000.

A new Communist Party of Slovakia was, however, founded in 1992 from a merger of the Communist Party of Slovakia – 91 and Communist League of Slovakia.

• 1944–1945: Karol Šmidke
• 1945–1951: Štefan Bašťovanský
• 1951–1953: Viliam Široký
• 1953–1963: Karol Bacílek
• 1963–1968: Alexander Dubček
• 1968: Vasiľ Biľak
• 1968–1969: Gustáv Husák
• 1969–1970: Štefan Sádovský
• 1970–1988: Jozef Lenárt
• 1988–1990: Ignác Janák

• 1969: Štefan Sádovský
• 1969–1988: Peter Colotka
• 1988–1989: Ivan Knotek
• 1989: Pavol Hrivnák
• 1989–1990: Milan Čič

Date	Leader	Votes		Seats			Position
		#	%	#	±	Size
1938	Banned. Hlinka's Slovak People's Party sole legal party.
1946	Karol Šmidke	489,596	30.61	31 / 100	31	2nd	Coalition
1948	Štefan Bašťovanský	as part of National Front		78 / 100	47	1st	Majority
1954	Karol Bacílek			47 / 103	28	1st	Majority
1960	Karol Bacílek			45 / 100	2	1st	Majority
1964	Alexander Dubček			58 / 92	13	1st	Majority
1971	Jozef Lenárt			102 / 150	44	1st	Majority
1976	Jozef Lenárt			101 / 150	1	1st	Majority
1981	Jozef Lenárt			102 / 150	1	1st	Majority
1986	Jozef Lenárt			103 / 150	1	1st	Majority
1990	Peter Weiss	450,855	13.35	22 / 150	81	4th	Opposition

• Communist Party of Bohemia and Moravia
• Communist Party of Slovakia – 91
• Communist Party of Slovakia
• Slovak Socialist Republic
• Central National Revolutionary Committee