The birth outcome for pregnant drug abusers is complicated by polydrug use, neonatal withdrawal symptoms, and low birth weight. To improve birth outcome, in‐hospital detoxification and stabilization from drug use followed by drug‐free residential living with prenatal care were provided for patients committed to cessation of illicit drug use. Pregnant heroin or cocaine abusers with significant drug use were eligible for the study. The birth outcome for the 30 term singletons born to the mothers in the program was statistically compared with respect to low birth weight, mean birth weight and length of stay in the nursery to that for 44 term singleton infants of a similar group of drug‐abusing ambulatory pregnant women in our aftercare clinic, not in the residential program. Twenty percent of 152 patients evaluated were found suitable for admission to the program. Numerical data for term singletons were as follows: weights (g ± SD), 3218 ± 596 (30) vs control 2806 ± 317 (44); low birth weights; 1/30 vs control 12/44; and length of stay in the nursery (days ± SD), 3 ± 0.5 (30) vs control 5.5 ± 2.5 (44). For the pregnant drug abuser committed to cessation of drug use, detoxification followed by drug free living leads to a statistically significant improvement in birth outcome.