Although maternal substance abuse in child welfare populations is a well-documented occurrence, little is known about the onset of these behaviors or the substance abuse histories of these mothers. Descriptive data from a small feasibility trial of mothers referred for substance abuse and child neglect suggest adolescent onset of hard substance use. Age of onset was associated with family history of use. The majority of mothers reported polysubstance abuse starting at an early age and quickly escalating patterns of behavior, including intravenous drug use. Implications for prevention efforts for children of families identified with substance abuse problems are discussed. Abstract published by arrangement with Taylor and Francis.