In 20 men with hypercholesterolaemia or mixed hyperlipaemia the effect was evaluated of treatment with Lovastatin and Colestipol on lipoproteins. Administration of the drugs in combination or alone decreased significantly the concentrations of total cholesterol (TC), LDL cholesterol (LDL-chol), and apolipoprotein B (apo B). The combination of Lovastatin in dose of 40 mg with Colestipol in dose of 10 g decreased more favourably the concentrations of TC (34.7%), LDL-chol (44.3%), and apo B (22.4%) than administration of each of the drugs alone in higher doses i.e. Lovastatin 80 mg (TC--26.8%, LDL-chol--31.8%, apo B--16.9%) or Colestipol 20 g (TC -20.0%, LDL-chol-26.3%, apo B-10.8%). The treatment with Lovastatin and Colestipol failed to change significantly the concentrations of triglycerides, HDL cholesterol and AI and AII apolipoproteins. The combined therapy was better tolerated than monotherapy.