Deforestation around large urban centers usually creates a fragmented landscape with reduced naturalareas. Biodiversity studies in these forest remnants provide useful tools for designing conservation strategies thatmaximize the persistence of local diversity and promote their connectivity. Inventories focused on particular taxahave been proposed as a useful mechanism that allows a better knowledge of the state of biodiversity in a given area,the butterflies are one of the taxonomic groups more frequently used for these studies. In this paper, we study thediversity and composition of the butterfly community in the cloud forest of the reserve El Romeral located southwestof the Medellín City in the Aburrá Valley, Colombia. We recorded 75 species belonging to 5 butterfly families, morethan recorded for similar forests associated with periurban areas. El Romeral shares only 50% of the species with themain periurban forest located east of the valley, indicating that each of the surrounding forest remnants of the citymay have a unique composition of species being complementary and useful for regional conservation.