This paper examines the correlates of problem gambling among a population of 220 methadone patients receiving treatment in the New York metropolitan area. Like most methadone patients, respondents were primarily adult males, ethnically mixed, of limited educational accomplishment and had long experiences with intravenous drug use. More than two-thirds of subjects had been convicted of one or more criminal offences. Analysis of the data showed seven percent of respondents to be probable pathological gamblers according to the South Oaks Gambling Screen (SOGS), indicating a high rate of gambling problems among this treatment population. Consistent with past studies, problem gamblers are more likely to be men, with histories of alcohol abuse, and with extensive criminal participation dating back to their teenage years. The data also suggested that problem gamblers who were also drug dependent were more likely to show greater evidence of social dysfunctionality compared to those who were exclusively substance abusers. More dually addicted respondents reported higher levels of recent heroin use, greater unemployment, and more reported hallucinations. Probable pathological gamblers who were substance abusers were also more likely to report being in conflict with their close friends. A multiple regression analysis suggested this to be the closest linked correlate to being a pathological gambler. Evidently, pathological gamblers create antipathy towards themselves as their compulsion to gamble is expressed; this in turn, may drive them toward further gambling, as they respond to this perceived opposition. These last preliminary findings will require further confirmation in future research.