There is some evidence that suggests a beneficial effect of calcium intake on serum lipid profile. The objective of this study was to determine the effect of 1000 mg calcium supplementation for 30 days on serum lipid profile in overweight or obese women. A double-blind, randomized clinical trial was conducted in 44 overweight or obese adult women (body mass index (BMI) >or=25 kg m(-2), age: 25+/-6y) receiving 1000 mg elemental calcium daily (n=24) or placebo (n=20). Serum lipids, lipoproteins and apolipoproteins including triglyceride, total cholesterol, HDL cholesterol (HDLc), LDLc, VLDLc, ApoA-I and ApoB were obtained at baseline and after intervention. Dietary calcium and energy intake were estimated using 24 h dietary recall for 3 days. Statistical analyses were performed using SPSS software. No significant differences were observed in dietary, anthropometric and serum variables between groups at baseline. Although serum total, LDL cholesterol and triglycerides tended to increase in both groups, total cholesterol elevation was significant only in placebo group (P=0.01). Triglyceride and VLDLc increased significantly only in the calcium group (P=0.03). LDLc elevation was significant in both groups (P<0.05). HDLc decreased significantly in both groups (P<0.01). Apolipoproteins did not change significantly in any group. No significant differences were observed in serum variables between groups after intervention. No considerable beneficial effect due to short-term calcium supplementation in overweight or obese women's lipid profile was observed.