The observations recorded here are of interest because of the histologic changes that occurred in the prostate gland during the administration of diethylstilbestrol. W. E. H., a white man aged 59, entered the Presbyterian Hospital on April 8, 1941 complaining of intermittent hematuria, difficulty in urination, backache, leg pains, loss of appetite, loss of weight and fatigue. These symptoms had become gradually worse during the past two years, and for the past six weeks he had relieved his urinary retention by daily catheterizations. Three years before, a transurethral resection was done in another hospital for the relief of urinary obstruction. He had had an increasing amount of pain in the lower lumbar region associated with sharp pains down the right thigh for the past seven months, and the intensity of these pains had increased to such an extent that it had become difficult for him to get around. During the past three