OBJECTIVE:There is some evidence for biomarker feedback when combined with cessation counseling for reducing smoking in pregnancy. This randomized controlled pilot study evaluated feasibility and potential efficacy of a social-cognitive theory (SCT)-based biomarker feedback intervention among pregnant Alaska Native (AN) smokers. METHODS:Participants were randomly assigned to receive three study calls (10-20 min each): (1) biomarker feedback intervention (n = 30) including personalized cotinine results and feedback on their baby's likely exposure to carcinogen metabolite NNAL, or (2) contact control usual care condition based on the 5As (n = 30). Assessments were conducted at baseline, post-treatment, and delivery. RESULTS:High rates of treatment compliance, study retention, and treatment acceptability were observed in both groups. 7-day point prevalence smoking abstinence rates at delivery verified with urinary cotinine were the same in both study groups (20% intent-to-treat analysis, 26% per-protocol). SCT-based measures did not change differentially from baseline by study group. CONCLUSION:This trial supports the feasibility and acceptability of providing biomarker feedback within the clinical care delivery system, but the intervention did not promote increased smoking cessation during pregnancy compared to usual care. PRACTICE IMPLICATIONS:Efforts are needed to promote the usual care and to develop alternative biomarker feedback messaging for pregnant AN women.