The role of serum lipids in the etiology of cholesterol gallstones and pigment gallstones was assessed in a case-control study. The study included 250 cases with surgically or ultrasonographically confirmed cholecystolithiasis and 526 hospital control patients. The highest gallstone risk was found at low high-density cholesterol levels and high triglyceride levels. An additional weakly negative association was found between total cholesterol level and gallstone risk. These findings were similar for cholesterol gallstones and pigment gallstones. The association between body mass index and gallstone risk disappeared after adjustment for serum lipids in a multivariate analysis. This study confirms previous reports on the association between gallstone risk and serum lipids. The similarity between cholesterol and pigment gallstones with regard to their association with serum lipids indicates that these types of gallstones share more causal factors than previously suggested. The absence of an effect of body mass index independent from serum lipids (as shown by the multivariate analysis) suggests that serum lipids are more closely linked to the pathogenesis of gallstones than obesity.