This study brings new data about the diurnal Lepidoptera of a protected area: The Nature Reserve Breana Roşcani Forest. There are no other available list of butterflies from this protected area. Natural Reserve Breana Roşcani Forest is located within the village Baneasa, situated in the NE of Galaţi. The forest covers an area of 154 hectares, of which 78.3 hectares were declared natural reserve since 1969. The reserve has forest and botanical character, here is met Romanian peony Peonia peregrina var. romanica, declared a natural monument. It is a xerothermophilic forest and includes species of oak, respectively, downy oak (Quercus pubescens) and gray oak (Quercus pedunculiflora) and bushes like Crataegus monogyna (hawthorn), Ligustrum vulgare (common privet) Prunus spinosa (blackthorn). The field research was undertaken in 2009 and 2010 from May to September. There were identified 39 species of butterflies belonging to 5 families: Hesperiidae, Papilionidae, Pieridae, Lycaenidae şi Nymphalidae. As it concern the presence on the Red List of Romanian butterflies, the species founded in the studied area belongs to the following categories: 69% are least concern species, 10% are near threatened species, 18% are vulnerable species and 3% are data deficient species. The most common species in the studied area are: Coenonympha pamphilus, Maniola jurtina, Vanessa cardui, Lasiommata megera, Issoria lathonia, Argynnis pandora. Euphrydias maturna partiensis Varga, 1973 – is a rare and localized species, it’s presence is reconfirmed for South Moldova, Carcharodus orientalis Reverdin, 1913 that is a rare and poorly known species was also identified in the studied area. Other species are protected, being included on the lists of Habitat Directive (Neptis hylas Linnaeus, 1758), Bern Convention and Red Data Book of European Butterflies (Glaucopsyche alexis Poda, 1761; Pseudophilotes schiffermuelleri Hemming, 1929).