Over the past 31/2 years we have used naloxone, a nonaddicting narcotic antagonist, as an adjunct in the treatment of 176 young heroin abusers in a highly structured day program. The current status of these 176 is as follows: 39% apparently are drug free (excluding alcohol and marihuana); 21% are in treatment programs; 21% are in prison, deceased, or lost to follow-up; and 1% are using illegal drugs. Naloxone was well tolerated by the abusers and was considered a valuable aid in the therapy of this difficult age group. The importance of the structure of the program itself in the treatment of the abuser is stressed.