Little is known about lay advice on prenatal alcohol and cigarette use and how this advice may complement or counteract advice from health professionals. In this study we examine the advice-giving role of female friends and relatives (“confidantes”). Survey data were collected from 105 low-income pregnant women about prenatal alcohol and cigarette use and confidante advice about these behaviors. Focus groups with 9 confidantes of pregnant smokers examined the advice they offered about substance use, their perceptions of these behaviors, and their roles as advice-givers. The rate of prenatal drinking was low among pregnant smokers, consistent with confidantes’ high risk perceptions and zero tolerance for drinking, but low risk perceptions and high tolerance for smoking. Confidantes described barriers to providing advice about smoking cessation. Because confidantes perceived their role to be distinct from, and in some ways more influential than, that of doctors their advice should be considered in the development of prenatal substance use interventions.