Objective: To examine the impact of maternal risky behaviors on the behaviors of children born to adolescent and young mothers. Methods: Adolescents and young Chinese mothers were recruited from an integrated young mother supportive program in Hong Kong between January and June 2015. Eligible mothers were asked to complete a questionnaire on their sociodemographic characteristics and history of risky behavior as well as their children's behaviors. Multiple regression analyses were conducted to explore the association between maternal risky behaviors and their children's behaviors. Results: Among 201 respondents, there were 187 (93.0%) ex-drinkers, 136 (67.7%) ex-smokers, and 83 (41.3%) ex-addicts. Compared to the reference group, children of mothers with drug use behaviors were more likely to have abnormal SDQ total difficulties scores (odds ratio 2.60, P=0.01), those of ex-drinking mothers had more behavioral difficulties and more conduct problems (B=3.82 and 1.37, P both=0.01) and those of ex-smoking mothers had more conduct problems (B=0.74, P=0.01) after adjustment for confounders. Children of active drug-taking mothers also had more emotional symptoms (B=1.77, P=0.04) and hyperactivity/inattention problems (B=2.14, P=0.03). Conclusion The history of mother's risky behavior was significantly associated with the behavioral problems of the children.