Sexually experienced male mice of the inbred strains C57BL/6j and DBA/2j differed significantly in speed of recovery of sex drive following an ejaculation; DBA/2j males recovered in 1 hr., while C57BL/6j males had had a median recovery time of 4 days. Males resulting from reciprocal crosses of these 2 strains resembled DBA/2j males in recovery time. A backcross to the C57BL/6j strain resulted in males which exhibited a median recovery time which fell between values of the 2 parent strains. A partial replication of the experiment supported the hypothesis that genotype is involved in determining recovery of sex drive in male mice. (PsycINFO Database Record (c) 2006 APA, all rights reserved)