It is found in South Europe, Asia Minor, southern Siberia, the Alay Mountains, Tian-Shan, Dzhungarsky Alatau, the Altai Region, the Sayan Mountains, Lake Baikal and Mongolia.

It is often confused with the small blue, a closely related species.

with the markings of the underside feebly shining through, narrow black margin and white fringes; beneath light ashy grey, the base dusted with blue, the ocelli and the median spot being very delicate.

In the Alps, locally plentiful, southwards to Italy, south-eastwards to Asia Minor and eastwards to the Altai.

The butterflies in the mountains, sporadic, in May and again from the end of June onwards.