In a group of 48 chronic hemodialysis patients, serum levels of coenzyme Q10 (CoQ) have been measured and appeared abnormally low in 62% of cases. Figures were positively correlated to those of serum vitamin E (vit E), although the latter were within a normal range. The chronic hemodialysis (CHD) patients with normal serum values of CoQ exhibited higher blood triglycerides. Pathologically low levels of serum vit E were found only in uremic subjects on conservative regimen with dietary restrictions and low compliance to protein-caloric intake. The reduced CoQ levels may contribute to the defective serum antioxidant activity and the increased peroxidative damage in uremic patients on CHD.