We analysed 890 faecal samples from 145 molossid bats in eastern Madagascar during the austral summer and winter. Coleoptera, Hemiptera, Lepidoptera and Diptera were the most important sources of food for Mops leucostigma, Mormopterus jugularis and Chaerephon pumilus. The percentage volume of Hemiptera and Lepidoptera were similar in the diet, pooled across season, for all species but significant differences were found for Diptera and Coleoptera. Mops leucostigma, however, had the highest volume of Diptera and M. jugularis of Coleoptera. Hemiptera were an important food source for all species during both seasons, whereas Coleoptera were prevalent in the diet only during the summer. Diptera were rarely eaten by M. jugularis but constituted a major source of food for the other two species during the winter. Although there was little evidence of strong interspecific dietary partitioning, M. jugularis appeared to have a more limited dietary composition at the ordinal level. Major differences in dietary composition were between season rather than species at the ordinal level. Further investigations are recommended to assess the potential role of molossids in consuming economic pests of cotton in Madagascar.