An increased capillary network has been observed in the skeletal muscle in patients with Restless Legs Syndrome (RLS) and bstructive sleep apnea syndrome (OSAS). These changes could be due to pregulation of growth factors responsible for angiogenesis. The aim of the study was to examine the occurrence and localization of VEGF and capillary proliferation in skeletal muscle of RLS (n=12), OSAS (n=12) and controls (n=11). Double-immunofluorescence staining for capillaries (CD31) and VEGF, and proliferating cells (Ki-67), was carried out on biopsies taken from the tibialis anterior. The percentage of capillaries expressing VEGF (CD31,VEGF+) was significantly higher in OSAS and RLS compared to controls. The percentage of proliferating apillaries (CD31,Ki-67+) was significantly higher in OSAS ompared with controls. In conclusion our study shows the occurrence of proliferation of endothelial cells in skeletal muscle in RLS and OSAS, supporting an upregulation of VEGF located in capillaries probably due to local hypoxia.