Recent compilations of species richness for 54 European countries and large islands and linear spatial autocorrelation modelling were used to infer the influence of area and environmental variables on the number of species of clearwing moths (Sesiidae) in Europe. Area corrected species richness of rhizophagous Sesiidae peaked at about 40°N and decreased towards higher and lower latitudes. Most species rich was Greece (45 species), Bulgaria (37), Italy (35) and Romania (35). The area corrected species richness of xylophagous Sesiidae peaked at about 45°N with France (24) and Italy (22) being most species rich. Species richness was significantly positively correlated with area and the average yearly difference in temperature, and significantly negatively correlated with latitude. Island and mainland SAR slopes did not differ significantly, however island species richness per unit area appeared to be about 2 to 2.5 times lower than mainland species richness.