His Excellency Koos Verdam
Koos Verdam in (1977)
Extraordinary Member of the Council of State
In office 1 March 1980 – 1 February 1985
Vice President	Marinus Ruppert (1980) Willem Scholten (1980–1985)
Queen's Commissioner of Utrecht
In office 16 March 1970 – 1 February 1980
Monarch	Juliana
Preceded by	Constant van Lynden van Sandenburg
Succeeded by	Pieter van Dijke
Member of the Senate
In office 23 May 1967 – 16 March 1970
Minister of the Interior
In office 5 September 1966 – 5 April 1967
Prime Minister	Jo Cals (1966) Jelle Zijlstra (1966–1967)
Preceded by	Ivo Samkalden (ad interim)
Succeeded by	Henk Beernink
Personal details
Born	Pieter Jacobus Verdam (1915-01-15)15 January 1915 Amsterdam, Netherlands
Died	11 March 1998(1998-03-11) (aged 83) Bilthoven, Netherlands
Political party	Christian Democratic Appeal (from 1980)
Other political affiliations	Anti-Revolutionary Party (until 1980)
Spouse	Jantina Boomsma ​ (m. 1943)​
Children	Louwrens Verdam (1947–2006) Tjeerd Jan Verdam (1948–2013) 5 other children
Alma mater	Vrije Universiteit Amsterdam (Bachelor of Laws, Master of Laws, Doctor of Philosophy)
Occupation	Politician · Jurist · Researcher · Academic administrator · Professor

Pieter Jacobus "Koos" Verdam (15 January 1915 – 11 March 1998) was a Dutch politician of the defunct Anti-Revolutionary Party (ARP) now merged into the Christian Democratic Appeal (CDA).

The reformed Verdam was a professor for Roman law and international civil law at the Vrije Universiteit Amsterdam and from 1959 to 1960 its Rector Magnificus. From 1966 to 1967 he was the Minister of the Interior and Kingdom Relations in the Zijlstra cabinet. In 1970 he became the Queen's Commissioner of Utrecht.

Honours

Ribbon bar	Honour	Country	Date	Comment
	Knight of the Order of the Netherlands Lion	Netherlands	3 June 1963
	Grand Officer of the Order of Orange-Nassau	Netherlands	1 February 1980	Elevated from Commander (27 April 1967)

Official

• Mr.Dr. P.J. (Koos) Verdam Parlement & Politiek (in Dutch)
• Mr.Dr. P.J. Verdam (ARP) Eerste Kamer der Staten-Generaal (in Dutch)