During the 5-year period 1977-1982, 57 patients below 35 years of age with secondary amenorrhea were assessed for hypergonadotropic (primary) ovarian failure. The histological findings within the ovaries as well as pertinent clinical and laboratory correlates are described. Nineteen had diagnostic ovarian biopsies performed. The importance of this technique is stressed. The ovaries of 14 patients showed absence of primordial follicles (true premature menopause); three others showed "resistant ovary syndrome" characterized by the presence of primordial follicles but little or no follicular development (including a case of galactosemia, in which the associated ovarian failure has been ascribed to follicular atresia). The remaining two revealed florid chronic perifollicular inflammatory reactions in the presence of both primordial and also developing follicles--one lymphoplasmacytic and the other granulomatous. The former has been previously suggested as evidence of an autoimmune process, but the latter has not hitherto been reported.