Fabry disease is an X-linked lysosomal storage disorder due to deficient activity of alpha-galactosidase A (alpha-Gal A) leading to renal insufficiency in males. The aim of present study was to investigate the level of alpha-Gal A activity and to determine the prevalence of Fabry disease in a Turkish male hemodialysis population. The activity of plasma alpha-Gal A was measured in a group of 808 male hemodialysis patients using fluorimetric methods. Patients with low alpha-Gal A activity were evaluated clinically and genetic testing was carried out. A correlation with creatinine, uric acid, urea, white blood cell (WBC), and high sensitivity (hs)CRP and alpha-Gal A activity was also investigated. Plasma a-Gal A activity among this male population undergoing hemodialysis was 7.88 +/- 5.18 mu M/hour/L (0.4055.72), significantly lower when compared to controls. No influence of creatinine, uric acid, WBC, or hsCRP on measured alpha-Gal A activity was reported. Two new Fabry disease patients were identified. Both were previously diagnosed with diabetes mellitus type 2. These findings provide, for the first time, data regarding the prevalence of alpha-Gal A deficiency (0.24%) in Turkish males receiving hemodialysis.