Courtship behavior in the male guppy (Poecilia reticulata) was analyzed employing 13 behavioral sequences measured in standardized situations. The stability of these measurements allowed a systematic study of individual differences and of their origins. Factorial analyses lead to two distinguishable main categories of behaviors: one was related to gonopodial swinging; the other to sigmoid display. Variables used to describe gonopodial swinging have only environmental correlates. The additive genetic component was null when estimated by two independent genetic analyses and this result was confirmed by a nonresponse to directional selection. On the contrary, most of the variables used to describe sigmoid display exhibit significant additive genetic components and this was confirmed by the incidence of males exhibiting vs. not exhibiting this behavior in a replicated directional selection. The adaptive significance of the variables is discussed in the light of genetic and observed correlations between the phenotypes.