Bt Cotton varieties are a new industry technology, which provide good control of boll/budworm populations. Bt Cotton varieties were tested in Northern Mexico under Commercial conditions from July to September 1998. The varieties were DP-33B, DP-35B, and DP5690 (Conventional variety). All Bt Cotton Varieties had good control of boll/budworm and reduced one application versus the conventional variety. DP-33B had the best yield, around 20%, versus conventional variety under Chihuahua, State conditions.