Psoriasis is a common relapsing dermatosis characterized by an increased epidermal cell proliferation. In this work we studied the lipid and lipoprotein pattern in 17 patients affected by long-standing psoriasis and in 20 normal controls. Total cholesterol, triglyceride, HDL-cholesterol and Apolipoprotein AI and B levels were measured; VLDL, LDL and HDL chemical composition was assessed by preparative ultracentrifugation. Plasma lipid and lipoprotein levels were significantly lower in the patient group; chemical analysis of the main lipoprotein classes showed compositional abnormalities consistent with an accelerated turnover of these particles. We believe that epidermal cell proliferation can play a role in determining these changes.