This study investigated the impact of a low-cost, pregnancy-specific self-help smoking-cessation program on patient smoking behavior both pre- and postpartum. The population consisted of 274 English-speaking women enrolled in a large health maintenance organization who reported smoking at the time of the baseline survey or had quit within the previous 3 months. A control group receiving standard obstetric care was compared with two experimental groups, one receiving the self-help materials and standard care and the other receiving the materials plus brief regular clinician interactions and counseling about smoking. Smoking data were obtained from two additional self-reported surveys conducted at 6 months' gestation and approximately 8 weeks postpartum. Self-reported smoking behavior was verified using a urine cotinine test, which revealed no significant differences between the groups. Among baseline smokers, although neither intervention yielded significantly higher 6-month nonsmoking rates compared with controls, both interventions significantly increased the proportion of women who were not smoking postpartum. Among those who had quit smoking at baseline, only the more intensive intervention significantly increased maintenance of non-smoking postpartum. Brief counseling, a simple charting system, and improved access to educational materials allowed the program to be integrated easily into routine prenatal care at a cost of $50-111 per patient.