It has been suggested that dietary fat increases the risk of breast cancer by elevating serum estrogen concentrations. However, studies on a relationship between fat intake and breast cancer risk have shown contradictory results, possibly because the levels of fat intake in study populations were too high to observe differences. Also, the effect of other dietary factors may present. The present study was performed to investigate the relationship between diet and estrogen metabolism in premenopausal women whose usual fat intake is relatively low compared to their western counterparts. Twenty lacto-ovo vegetarians (LOV) and twenty omnivores participated in the study. Three day food records including a Saturday or a Sunday were used to estimate nutrient intake. Serum lipids, estradiol, sex-hormone binding globulin, and urinary estradiol were measured. Study results showed $24.8\%$ and $20.9\%$ of energy intake were provided from fat in omnivorous and LOV subjects, respectively. Serum and urinary levels of estradiol were two times higher in omnivores. Fat intake was not related to either serum estradiol nor urinary estradiol when the Spearman correlation coefficient analysis was performed. Carbohydrate, total dietary fiber and soluble dietary fiber intakes were negatively related to serum estradiol concentration. Legumes, vegetables and fruit consumption showed significantly negative relationships with both serum and urinary estradiol concentrations. These results indicate lower estrogen availability may be associated with plant food­based diets in premenopausal women whose usual diets contain less than $25\%$ of energy as fat.