In this family, two affected boys have perineal hypospadias and bifid scrotum, and two affected girls have slight clitoral enlargement with otherwise normal genitalia. All are mild ‘salt-losers’ with spontaneous crises occurring late (3 months and 2 years) in the boys. The girls had negative Na+ balance only when stressed by salt deprivation at ages 2 months and 4 years. All had elevated 17-ketosteroid excretion when diagnosed and, in the 2 youngest, urinary DHA > androsterone. Cortisol production and/or 17-OH-corticosteroid excretions were normal. Steroid excretion patterns showed an increase of 3β-HSD activity with increased age, but with a persisting high excretion of Δ4-pregnanetriol (Δ5-p′triol). At 2 months, one girl excreted per 24 h: pregnanetriol (p′triol)-0.23 mg, Δ5-p′triol-1.2 mg, 17α-OH-pregnenolone-2.6 mg, 16α-OH-pregnenolone-8.2 mg, 16α-OH-DHA-5.4 mg, DHA-0.5 mg. Her sister, at age 10 years, during withdrawl of cortisone therapy, excreted per 24 h: p′triol-24 mg, Δ5-p′triol-14 mg, DHA-1.2 mg, no 16α-OH-pregnenolone or 16α-OH-DHA. We conclude that these cases have partial 3β-HSD deficiencies, on the basis of the inadequate fetal virilization and persistent post-natal excretion of large amounts of Δ5-′triol; and partial 21-hydroxylase deficiencies, on the basis of the high p′triol excretions. The low post-natal excretion of DHA, relative to Δ5-p′triol and 17α-OH-pregnenolone, may be due to a late fetal appearance of the 3β-HSD for DHA or may be due to an underactivity of the 17–20 desmolase (side-chain splitting) enzyme.