Previous research on elderly women living in institutions has showm a postiive relationship between the administration of estrogen and improved psychologic status. In the current 12-month study, the effects of estrogen therapy were compared in 18 institutional women versus 21 noninstitutional women who volunteered to participate. Both groups received conjugated estrogens (Premarin, 0.3 mg daily) in interrupted courses. Throughout the year, the women were evaluated by means of the Eysenck Personality Inventory, the Profile of Mood States, the Lawson Morale Scale, and various self-perception items. Statistically, significant changes occurred in the areas of neuroticism, tension, morale, and subjective mood states, but the improvement was greater in the institutional subjects. The main conclusion was that estrogen therapy has a positive effect upon psychologic status, particularly for women who reside in an institution.