The relationship between heroin use and street crime has been studied for the better part of this century, but the findings have been inconclusive. Research in this area has been limited to analyses of criminality in terms of arrest data, and samples have been drawn only from officially known populations of drug users. The present study focuses on a sample of 356 active heroin users from Miami, Florida, and data have been collected de scribing their officially known and self-reported criminal activity. The data indicate that, while active heroin users are heavily involved in street crime, any relationship between drug use and crime is much more complex than has been generally believed. The findings of the research suggest that the wrong questions may have been asked in previous studies of the drugs/crime nexus.