Information about lifetime intravenous drug use (IVDU) was obtained from 1,062 relatives of hospitalized alcoholics, felons, and control subjects, of whom 92 had a history of IVDU and an additional 230 had a history of substantial, but non-IV drug use. The IVDUs were significantly more likely than all other subjects to have reported experiencing numerous behavioral and social difficulties relating to conduct difficulties, early initiation of substance use, and disrupted living situation before the age of 15. They were also more likely to have exhibited conduct problems than other drug users. In multivariate analyses, four symptoms (fighting in school, juvenile arrest, initiation of cannabis use before 15, or initiation of sexual activity before 15) differentiated IVDUs. A history of greater numbers of these problems was associated with increasing risk for IVDU, both when compared with the total sample and when compared with other drug users.