Uterine arteriovenous malformations are rare lesions with a considerable risk potential. Clinical presentation varies from no signs over various degrees of menorrhagia to massive life threatening vaginal bleeding. This is the first report of congenital uterine arteriovenous malformations in two patients with primary infertility. In one case, the uterine lesions were found in conjunction with other congenital malformations suggesting the diagnosis of hemihyperplasia/lipomatosis syndrome. Etiology, symptoms, diagnostic and therapeutic work-up are discussed; pathological findings are illustrated.