In the Mediterranean landscape fires are common, sometimes arising due to human activity. Fire influences the amount of sunlight that reaches the ground, thus affecting the diversity and distribution of animal and plant species. In this study, we analysed the effect of fire on butterfly diversity at the Site of Community Importance (SCI) 'Monti di Lauro' (IT8040013) in southern Italy (Campania). The area covers 7040 ha and is mainly characterised by Mediterranean maquis and woody vegetation. We compared the flight activity of butterflies before and after a fire incident in October 2008. Weekly transects were made from April to September in 2008 and 2009. From the transect data, we calculated several diversity indices. We surveyed 55 species and 5052 individuals (2008: 43 species, 1764 individuals; 2009: 49 species, 3288 individuals). Inter-year comparisons showed that richness was significantly lower in 2008 than in 2009, as well as the abundance; the evenness index was significantly higher in 2008 than in 2009. Intra-year comparisons before fire (2008) showed significant differences among months in all indices analysed, whereas after fire (2009), only evenness differed significantly. Our results show that after fire in the Mediterranean maquis, a rapid change in butterfly community structure occurred, increasing both species and individual abundance. Nevertheless, a lower evenness indicates a less balanced butterfly community after fire. Notably, Melanargia arge, a protected species by the Habitats Directive, was not observed following the fire. © 2014 Unione Zoologica Italiana.