In Drosophila some individuals are more successful at mating than others. Reproductive fitness is strongly dependent upon the ability to recognize and compete for members of the opposite sex. Experiments were designed to answer two questions. (i) What behavioral components are characteristic or predictive of successful courtship? and (ii) How important is the information transmitted in the different sensory channels for courtship success in each sex? These questions were approached by two experimental procedures. Flies having a sensory deficiency (olfactory, auditory, or visual) competed with wild-type flies of the same sex for mates. Males were found to rely upon sensory channels different from those used by females in order to court successfully. In addition, the courtships of pairs of various genotypes were recorded and subjected to multivariate analysis. The multivariate courtship profiles deviated most widely from those of successful wild-type pairs when the male or female was unable to receive information in the sensory channel most important for successful mating by that sex. Both sequential and quantitative courtship properties were altered when one participant was deficient in ability to receive certain sensory information.