The following people are credited as replacements or additions if they were not credited on opening night.

Brian Cox	Marc
Henry Goodman	Serge
David Haig	Yvan
Buck Henry	Marc	(circa. May 11, 1999-Aug 8, 1999)
Judd Hirsch	Marc	(Dec 22, 1998 - ?)
Wayne Knight	Yvan	(circa. May 11, 1999-Aug 8, 1999)
Joe Morton	Serge	(Dec 22, 1998 - ?)
George Segal	Serge	(circa. May 11, 1999-Aug 8, 1999)
George Wendt	Yvan	(Dec 22, 1998 - ?)

Understudies: Thomas Schall (Serge, Yvan), Henry Strozier (Marc, Yvan), Jack Willis (Yvan).