Limited research shows that correlates of substance use differ for mothers and nonmothers. This study compares mothers and nonmothers by examining the relationship between perceived social support and frequency of crack/cocaine use. Data for the 307 female prisoners in this sample were collected between 2007 and 2008 in four US states during the Criminal Justice-Drug Abuse Treatment Studies' (CJ-DATS) Reducing Risky Relationships for HIV protocol. Ordinary least squares regression models revealed that greater social support was significantly associated with less frequent crack/cocaine use among mothers but not nonmothers. Implications are discussed. This research was supported by the National Institute on Drug Abuse.