The nornicotine content of cultivars released by the University of Kentucky and University of Tennessee tobacco breeding program has been reduced by eliminating plants exceeding 3% conversion of nicotine to nornicotine (nornicotine/nicotine + nornicotine) from foundation seed stocks. These cultivars have been released as low converter (LC) versions of the original cultivars. A study was conducted in 2004 and 2005 at four locations in Kentucky and Tennessee to determine the impact of reduced nicotine to nornicotine conversion on levels of tobacco specific nitrosamines (TSNA) in Burley tobacco. Three replications of 15 cultivars were grown at each of four locations, with data analyzed as a split-plot design with locations as whole plots and cultivars as subplots. Highly significant differences were detected among locations and among cultivars for nicotine conversion and nitroso-nornicotine (NNN) and total TSNA levels. As expected, a highly significant correlation was found between percent conversion and NNN (r²=0.75, Pr>|r| = 0.001), and between percent conversion and TSNA (r²=0.58, Pr>|r| = 0.02). However, significant differences for NNN were also detected among cultivars that were not significantly different for nicotine conversion. The cultivars having low levels of NNN also had significantly lower levels of nitroso-anatabine (NAT) and nitroso-nicotine (NNK). KT 204LC, the variety having the lowest level of total TSNA, had means of 3.88% nicotine conversion, 0.64 ppm NNN, 0.89 ppm NAT, and 0.07 ppm NNK. In comparison, ms KY 14XL8 had means of 3.78% conversion, 1.87 ppm NNN, 4.56 ppm NAT, and 0.59 ppm NNK. The three cultivars having the lowest levels of TSNA were hybrid varieties that had a common parent, suggesting that genetic differences may account for the variation in TSNA observed. The results from the study demonstrate that reducing nicotine to nornicotine conversion is effective in reducing NNN, but breeding for reduced total TSNA may also be possible.