The discovery of the butterfly False Ringelt (Coenonympha oedippus F.) in two localities in Istria, between Marusici, Vranjak and Sterna (VL02, VL03) and in the valley of the Mirna Valley near Buzet (VL12) has reconfirmed this species as a member of the fauna of Croatia. At the same time, a review of the collection of the Croatian Natural History Museum has shown that specimens catalogued as C. oedippus from Mt Velebit are either not from Croatia or belong to the species Aphantopus hyperantus. There is an urgent necessity to establish the precise range and size of the population and the degree of threat to it, and to undertake legislative and active measures for the conservation of the remaining habitats of this butterfly in Croatia, since it is one of the most endangered animal species in Europe.