Data from the National Pork Producers Council Maternal Line National Genetic Evaluation Program were used to compare the sow longevity of six different genetic lines, and to estimate the associations of gilt backfat thickness, age at first farrowing, litter size at first farrowing, litter weight at first farrowing, average feed intake during lactation, and average backfat loss during lactation with sow longevity. The lines evaluated were American Diamond Genetics, Danbred North America, Dekalb-Monsanto DK44, Dekalb-Monsanto GPK347, Newsham Hybrids, and National Swine Registry. The results suggest that the sows of Dekalb-Monsanto GPK347 had a clearly lower risk of being culled than the sows of other five lines. Moreover, the shape of the survival distribution function of Delkab- Monsanto GPK347 is clearly different than the other five lines. There were high culling rates due to reproductive failure after first weaning in the sows of the five other lines, however this increased culling rate did not exist in the Dekalb-Monsanto GPK347 line. The results further suggest that sows with lower feed intake and greaterer backfat loss during lactation had the shorter productive lifetime. These between line differences indicate that it is possible to select for sow longevity. More research is needed to show the most efficient methods to select for sow longevity.