BACKGROUND: Increased concentrations of low density lipoprotein cholesterol (LDL-C), as well as of small dense LDL-C (sdLDL-C), are considered as cardiovascular risk factors. OBJECTIVE: An assessment of the effects of ezetimibe and orlistat administration, alone or in combination, on LDL-C and sdLDL-C levels (primary endpoint), as well as on anthropometric variables and metabolic parameters (secondary endpoints) in overweight and obese patients [body mass index (BMI)>28 kg/m(2)] with hypercholesterolaemia [total cholesterol>200 mg/dL (5.2 mmol/L)]. METHODS: Eighty six subjects were prescribed a low-fat low-calorie diet and were randomly allocated to receive orlistat 120 mg, 3 times daily (O group), ezetimibe 10 mg/day (E group) or both (OE group) for 6 months. RESULTS: Significant reductions in LDL-C (-19%, -21%, -32% in groups O, E and OE, respectively, all p<0.01 vs. baseline) and sdLDL-C levels (-45%, -48%, -76% in groups O, E, OE, respectively, all p<0.01 vs. baseline) were observed. Group OE experienced a significantly greater reduction in LDL-C and sdLDL-C levels compared with groups O and E (p<0.05). Furthermore, significant reductions of BMI, homeostasis model assessment (HOMA) index, serum uric acid, transaminase activities and plasma lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) activity were observed in the O and OE groups. Gamma-glutamyl transpeptidase activity and Lp-PLA(2) activity improved significantly more with the combination treatment compared with either orlistat or ezetimibe monotherapy. CONCLUSIONS: Orlistat and ezetimibe combination had a more favourable effect on LDL-C and sdLDL-C levels in overweight and obese hypercholesterolaemic patients than either drug alone. Furthermore, orlistat, alone or in combination with ezetimibe, additionally improved several anthropometric and metabolic variables.