Tamoxifen has been used for a long time as a hormonal treatment in breast cancer. Recent studies in pre and postmenopausal women have shown that tamoxifen exhibits favorable effects on the lipid profile. In this study we investigated the effects of tamoxifen on lipid profile and hepatic steatosis. Fifty two (31 postmenopausal and 21 premenopausal) women with breast cancer treated with tamoxifen at a dose of 20 mg daily were included in the study. Serum lipid parameters (total cholesterol, high and low density lipoprotein cholesterol and triglyceride) were measured baseline and at the 6th month of tamoxifen treatment. Upper abdominal ultrasonography was performed before and at the 6th month of therapy for assessment of liver steatosis. We obtained decreased levels of serum total cholesterol after 6 months of tamoxifen treatment (p < 0.05). However, we did not detect any changes in triglyceride and high-density lipoprotein cholesterol levels (p > 0.05). Increased liver steatosis was observed in 22 patients (42.3%) after tamoxifen treatment. We could not detect increase in lipid levels in these patients. There was no significant difference between the lipid levels in the patients with increased liver steatosis and stable or no liver steatosis. Whether hepatic steatosis is dependent on lipid changes in tamoxifen use should be further investigated.