Background Statin-fibrate combinations are very effective in the treatment of familial combined hyperlipidaemia (FCHL). Nonetheless, they have not been extensively used because of the fear of side effects. Thus, a therapeutic alternative is required for this lipid disorder. Objective To compare the long-term (one-year) efficacy of atorvastatin monotherapy with those of four statin-fibrate combinations in 675 FCHL patients. Methods Patients were randomly assigned to atorvastatin monotherapy (A 20 mg/day) n=134, or pravastatin (P 20 mg/day)+gemfibrozil (G 1200 mg/day) n=135, simvastatin (S 20 mg/day)+G (1200 mg/day) n=137, P (20 mg/day)+ci-ciprofibrate (C 100 mg/day) n=135, and S (20 mg/day)+C (100 mg/day) n=134. Results Twelve patients on statin-fibrate combinations were withdrawn from the study because of side effects: three because of CK elevation, two because of myalgia and seven due to increase in serum transaminase levels. One patient on A was withdrawn because of persistent epigastric discomfort. Atorvastatin reduced low density lipoprotein cholesterol and apoprotein B more than all four combinations (-45% vs. maximum -40% of S+C, and -39% vs. maximum -32% of the same combination, respectively, P<0.001 for both), but had a lesser effect on triglycerides (-38% vs. maximum -53% of S+C, P=0.0002) and high density lipoprotein cholesterol (6% vs. maximum 21% of S+G, P=0.0003). The effect of A on plasma fibrinogen was analogous to that of G combinations (-8% vs. -9% of P+G and -11% of S+G, P=NS vs. baseline and among each other) and inferior to that of the ciprofibrate combinations (-8% vs. -24% of P+C, P=0.0002 and -26% S+C, P=0.0001). A had a lower treatment cost and better patient compliance, P=0.04 vs. C combinations and P=0.02 vs. G combinations. Conclusions The data suggest that statin-fibrate combinations have a beneficial effect on all lipid parameters. Atorvastatin monotherapy has a better effect on LDL-C and apoprotein B than statin-fibrate combinations, but a lesser effect on HDL-C, TG and in the case of ciprofibrate combinations, fibrinogen. The clinical significance of these findings should be tested in a large, long-term survival study.