Mutations on the period locus of Drosophila melanogaster influence circadian periods as well as the rhythm in inter-pulse intervals in male courtship song; perL mutations produce long circadian periods and courtship song rhythms and per(s) mutations produce short circadian periods and courtship song rhythms. Thus, these mutations influence timing mechanisms over both long and short behavioral time horizons. We examined if the mean courtship duration of male Drosophila melanogaster cycles rhythmically, and if mutations at the period locus influence courtship bout duration. We measured the courtship bout durations of the following: (1) wild type Canton-S (per+) males; (2) perL males; and (3)per(s) males. Rhythmicity of courtship bout duration could not be mathematically determined. Mean courtship bout duration did not differ among the three groups; thus, mutations at the period locus did not influence mean courtship duration. There was a nonsignificant trend for per+ males that were successful at mating to have longer mean courtship duration than unsuccessful males.