Renal anemia improves after L-Carnitine (L-C) administration to patients on chronic dialysis due to causes that remain unclear. Our study was designed on dialysis patients to investigate effects of L-C on anemia and on erythrocyte survival (ES) which is important in anemia. This study consisted 15 Hemodialysis (HD), 16 Continuous Ambulatory Peritoneal Dialysis (DAPD) patients and 44 healthy subjects. Patients received L-C 2 g /day for 4 m onths then 20-25 mg/kg 3 days a week, for following 12 months. At initial, after 4 and 16 months biochemically, and initial, after 6, 12 months ES were investigated. Initial free carnitine (FC) level in patients (was lower than that of controls and increased during 16 months. An increase in Haemoglobin -Hb, Hematocrit-Htc, Erythrocytes —Er was occurred 4 months after, and continued in following 12 months. ES was prolonged from 16±6 days to 22.6±10days in 6th and to 24.2±6 days in 12th months. In serum, Albumin (Alb) increased, creatinin decreased in 16th month in DAPD group. Alb increased , urea decreased n HD group. Our findings suggest that the improvement in anemia was mainly due to prolonged ES with L-C treatment. We also thought that L-C might has an effect on Hb sentesis