The relationship between serum carnitine levels and erythrocyte osmotic fragility was investigated in 26 chronic hemodialysis patients (10 males and 16 females, mean age: 57.3 ± 13.5 years). Serum total-carnitine (TC), free-carnitine (FC) and acyl-carnitine (AC) levels were determined by a spectrophotometric method. Erythrocyte osmotic fragility was measured with a coil planet centrifuge. Serum TC levels were 39.9 ± 13.4 μmol/l (mean ± SD), FC levels were 21.8 ± 7.8 μmol/l and AC levels were 18.0 ± 9.6 μmol/l. The mean hemolysis end point (HEP) was 67.4 ± 5.4 mOsM, the hemolysis maximum point (HMP) was 86.3 ± 5.4 mOsM and the hemolysis start point (HSP) was 101.2 ± 4.4 mOsM. Each hemolysis point in hemodialysis patients was elevated in comparison with the normal range. There were no significant differences in hemolysis points between a recombinant human erythropoietin (rhEPO)-treated group and nontreated group. HEP correlated with serum TC (r = -0.56, p < 0.01) and AC levels (r = -0.58, p < 0.01). HMP correlated with serum TC (r = -0.42, p < 0.05) and FC levels (r = -0.41, p < 0.05). Dose requirement of rhEPO maintaining target hematocrit correlated with serum TC (r = -0.54, p < 0.05) and FC levels (r = -0.50, p < 0.05). These data support that low serum carnitine levels accelerate erythrocyte osmotic fragility. Carnitine may contribute to the metabolism of erythrocyte membrane and have an impact on the efficacy of rhEPO in correcting renal anemia.