A study based on interviews with 225 property offenders in New South Wales prisons provides information on the relationships between crimes such as armed robbery and burglary and regular heroin use. were users of barbiturates, cocaine, heroin, and/or other opiates/narcotics on a regular or heavy basis prior to arrest. Most users, 89.7 percent, said that the need for money to support their heroin habit was the main reason for their offense. Nonusers' reasons were far more varied, the most common being unemployment followed by under the influence of alcohol and/or drugs and money for support. Self-reports showed that users were more likely to have committed more armed robberies, burglaries, and frauds than nonusers. There was a greater likelihood that users would progress from the initial commission of a crime to the regular commission of that crime. Most heroin users reported having committed a property crime before their first use of heroin, and it wasn't until they became regular users that they committed more serious crimes. Tables and 20 references. (Author abstract modified)