PURPOSE: To use direct observations of first prenatal visits to describe obstetric providers' adherence to the evidence-based clinical practice guideline for smoking cessation counseling recommended by the American College of Obstetricians and Gynecologists, the 5 A's (Ask, Advice, Assess, Assist, and Arrange). DESIGN: Observational study using audio recordings of first obstetric visits. SETTING: An urban academic hospital-based clinic. PARTICIPANTS: Obstetric care providers and pregnant women attending their first obstetric visit. METHOD: First obstetric visits were audio recorded. Visits were identified in which patients reported smoking, and discussions were analyzed for obstetric providers' use of the 5 A's in smoking cessation counseling. RESULTS: Obstetric providers asked about smoking in 98% of the 116 visits analyzed, but used 3 or more of the 5 A's in only 21% (24) of visits. In no visits did providers use all 5 A's. In 54% of the visits, providers gave patients information about smoking, most commonly about risks associated with perinatal smoking. CONCLUSION: Few obstetric care providers performed the recommended 5 A's smoking cessation counseling with their pregnant smokers. Effective and innovative methods are needed to improve obstetric providers' use of the 5 A's.