A validated method for the determination of four tobacco-specific nitrosamines (TSNAs) – NNAL, NNN, NAT, and NAB – was compared to a method published in 2009 in the Journal of Chromatography B 877: 1185-1192, by Kavvadias, Scherer, et al. Single sets of calibration standards and quality control samples, which covered the full analytical range of each analyte in both methods, were utilized. The analytical range for NNN differed the most between the methods, with the Celerion method covering 0.200 – 40.0 pg/mL and the published method covering 2.00 – 250 pg/mL. In total, 20 urine lots (10 from nonsmokers and 10 from smokers) were assayed with each method for a comparison of the basal concentrations of each TSNA. Selectivity and matrix effect were assessed by comparing the quantitative accuracy of each method when known amounts of the TSNAs were added to the basal concentrations. Basal concentrations of the TSNAs compared within 20% for 8/10 smoker lots for NNAL, 7/10 smoker lots for NAT, 6/10 smoker lots for NAB, but only 2/10 smoker lots for NNN. For some of the smoker urine lots, the differences in the basal concentrations of NNN were substantially different. A summary of the results is presented, including sample chromatography, and possible reasons for differences between the methods are discussed.