Congenital adrenal hyperplasia (CAH) occurring in twins is extremely rare. Most of these cases are of classic salt-wasting CAH due to 21-hydroxylase enzyme deficiency. Only two cases of the simple virilising form of CAH have been reported previously, with variable clinical presentations. In this report, we describe a pair of monozygotic twins with classic simple virilising form of CAH, who had a simultaneous onset and similar severity of clinical manifestations. Genetic analysis of the CYP21A2 gene in twin 1 showed the pres-ence of two heterozygous pathogenic sequence variants, c.518T>A and c.955C>T in the CYP21A2 gene, consistent with a diagnosis of CAH due to 21-hydroxylase deficiency. We also present a brief review of previous cases of twins with CAH.