Taurine is one of the most abundant amino acids found in the tissues of insect nervous systems. The distribution of taurine-like immunoreactivity was investigated in compound eyes, ocelli and mushroom bodies of Drosophila and Locusta. A comparison to the previously described taurine-like immunoreactivity in the brain of worker honeybees (J. Comp. Neurol., 268 (1988) 60-70) showed that the photoreceptor cells of all three insect species are immunoreactive. Immunoreactive mushroom body intrinsic Kenyon cells were also found in all three species. The intensity of the immunoreactivity was however graded, depending on the species. While the majority of Kenyon cells were stained in Apis and Drosophila, the immunoreactivity of the locust mushroom body was mainly confined to the intrinsic neurons originating in the accessory calyx.