The subjects had a median age of 26 years, at least 3 years of heroin use, and less than 6 months confinement in a correctional facility prior to their taped interviews. In addition, none had been involved in a drug treatment program during the last month on the street. One-third derived large portions of their incomes from legal sources, one-third were primarily involved in distribution-related activities, and many had participated in burglaries and muggings. Addicted respondents had relied much more heavily on illegal activities than had nonaddicted subjects. The interviews revealed 28 different types of empirically derived activity patterns for the 22 addicts, and among these three major patterns emerged as the most frequent. A total of 11 respondents reported average-sized hustling successes followed by average amounts of drug use; 14 subjects reported higher-than-average hustling successes followed by higher-than-usual drug use, which in turn, was followed by either diminished hustling or by no hustling at all. Also, 15 subjects reported poorer-than-average successes followed by lower-than-usual drug use, which was usually followed by the immediate resumption of hustling activity. Factors affecting the development of other patterns are reviewed. Most of the six nonaddicted subjects used drugs on weekends; and when hustling activity occurred it usually involved gambling on a recreational basis. Related studies are reviewed, and an 11-item reference list is included.