Studies were made of 36 different nuts, grains, fruits and vegetables commonly used as human foods; each of these was fed to a group of ovariectomized rats for 10 days as a sole diet. The estrogenic activities of the foods were estimated by comparing the uterine weights, uterine fluid volumes and the vaginal cornification indices of each group of rats with those of groups fed other foods. Almonds, cashew nuts, peanuts, oats, corn, wheat and apples all showed estrogenic activity. The original sample of almonds showed the greatest estrogenic activity (p less than 0.01) which was confirmed by repetition of the experiment (p less than 0.01), but subsequent studies of other samples of almonds showed no estrogenic activity. Possible reasons for the disparity of the results with different lots of almonds are discussed.