We examine the effect of total annual food abundance and seasonal availability on the biomass and species richness for frugivorous primates on three continents (n=16 sites) by data on fruit fall. We reveal that the best-fit models for predicting primate biomass include total annual fruit fall (positive), seasonality (negative) and biogeography (Old World>New World and mainland>island) and that these factors explain 56–67% of the variation. For the number of species, the best-fit models include seasonality (negative) and biogeography (Old World>New World and mainland>island) but not total annual fruit fall. Annual temperature has additional effects on primate biomass when the effects of fruits and biogeography are controlled, but there is no such effect on species richness. The present results indicate that, measured on local scales, primate biomass and number of species is affected by the seasonal variation in food availability.