A preliminary checklist of butterflies collected in the Caldera de Lubá is presented. Of the 70 species cited, 14 represent the first records from Bioko (Graphium ucalegon ucalegon, Nepheronia argia argia, Pentila fidonioides, Cymothoe althea, Cymothoe capella, Cymothoe consanguis, Lachnoptera anticlia, Amauris vashti, Bicyclus golo, Bicyclus neustetteri, Coeliades forestan, Ceratrichia phocion camerona, Celaenorrhinus plagiatus and Semalea pulvina). From the results obtained after applying different diversity indices (richness, dominance, evenness) and accumulation functions, we can infer that the Rhopalocera of the Gran Caldera de Lubá constitute an extraordinarily diverse community of great evenness, lacking generally highly threatened taxa or species with a localized occurrence on Bioko and, collectively, the fauna is characterized by a highly even and stable structure. The results obtained can provide the tools to develop conservation measures in the future, as well as to strengthen the creation of Scientific Reserves used as genetic resources warehouse.