Objective: Our objective was to evaluate the direct effect of tamoxifen citrate (TAM) on the endometrium, liver, breast tissue and the lipid profile in oophorectomized (OX) rats. Study Design: An experimental animal study. Material and Methods: Forty-one mature rats (33 OX) were randomly divided into four groups and received either TAM (0.4 or 0.8 mg/kg p.o.) therapy or placebo over 60 days as follows: (1) sham; (2) OX + TAM (0.4 mg/kg); (3) OX + TAM (0.8 mg/kg); (4) OX. All histological changes in the endometrium, liver and breast tissue were evaluated under the light microscope by comparing the TAM-treated groups with the OX and sham-operated groups. Blood total cholesterol and low-density lipoprotein cholesterol levels were also analyzed. Results: TAM-treated rats showed a significant reduction in body weight, blood cholesterol and low-density lipoprotein cholesterol levels, but the wet uterine weight was not affected. Estrogenic effects of TAM were not detected with either dosage on the endometrium. TAM-treated groups showed atrophic breast tissue. No histopathological changes were detected in the liver with TAM treatment. Conclusion: The data suggests that TAM may not act as an estrogen receptor agonist with the given dosage on the endometrium in OX rats. Two different doses of TAM do not cause histological changes in liver over 60 days of treatment.