This study investigated the relationship of clinicians' knowledge of treatments for nicotine dependence during pregnancy and postpartum and explored what provider characteristics are associated with knowledge levels. Survey data from community health center (CHC)-based prenatal, pediatric (PED), and WIC program (Special Supplemental Nutrition Program for Women, Infants, and Children) providers participating in a randomized clinical study were used. Providers reported low awareness of the health risks of smoking to the developing fetus/child of pregnant and postpartum women and of the effectiveness of nicotine replacement therapy (NRT) for doubling quit rates. Obstetric (OB) and WIC providers were more aware than PED providers that provider-delivered interventions are effective. Confidence in using counseling steps was significantly associated with general and NRT-related knowledge. NRT-related knowledge, but not general knowledge, was associated with higher performance of intervention steps. Educational programs targeting OB, WIC, and PED providers' knowledge about effective smoking cessation counseling strategies and their confidence in being effective with patients are needed.