A shortened approach to the measurement of 17α-hydroxyprogesterone (17-OHP) is described. The extracted plasma sample with 3H indicator is purified by only one paper chromatography. No acetylation step or further chromatography is necessary. Values obtained in males and females are the same as reported by Strott et al. Both LH and FSH increased plasma 17-OHP in men. Measurable, but low, plasma values were observed in prepubertal children. Further evidence for adrenal secretion was provided by values from children and castrates, and by failure to suppress 17-OHP during the follicular phase with estrogen.