To determine the reliability of self-reported smoking status in the orthopaedic trauma population and determine if certain patient factors might predispose inaccurate self-reported smoking cessation. Prospective. Level I trauma center. Two hundred forty-seven orthopaedic trauma patients were included in the study. In-office measurement of exhaled carbon monoxide (CO). Self-reported smoking cessation with exhaled CO measurements. A total of 906 self-reported surveys were completed over 4 follow-up visits. Of the responses indicating smoking cessation (n = 174), 12.6% [95% confidence interval (CI), 0.081-0.185] reported smoking cessation with positive CO readings, suggesting inaccurate self-reporting of smoking status. Over 20% of those patients inaccurately reporting abstinence did so more than once. The odds of inaccurate self-reporting was 3 times higher in patients with no insurance or government insurance [odds ratio (OR), 3.5; 95% CI, 1.1-11.0; P = 0.043] and in the unemployed (OR, 3.3; 95% CI, 0.97-8.57; P = 0.049). Self-reported smoking status in the orthopaedic population is fairly reliable, with 13% of patient's inaccurately self-reporting smoking cessation despite knowing their smoking status was being measured. Clinicians should be aware of the potential for inaccuracy in self-reported smoking cessation, particularly in patients with the identified socioeconomic factors. Point-of-care testing before elective trauma procedures to confirm smoking status might have a role if the procedure outcome is highly dependent on smoking status. Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.