Summary A study is reported concerning the alteration in voluntary food intake of adult female Sprague-Dawley-Rolfsmeyer rats following thyro-parathyroidectomy and adre-nalectomy separately and together. Food consumption declined gradually to 24% at about 60 days following thyroidectomy. After 119 days, graded replacement therapy with thy-roxine was initiated. Levels of 0.5, 1.0, and 2.0 μg/100 g body weight failed to stimulate food intake comparable to the control level. Even on 2.0μg thyroxine after 189 days, food intake was still 31% below normal. After adrenalectomy, food intake was quickly reduced 27%, and after the thyroids were removed, food intake was reduced a total of 30%.