Fourteen cotton varieties with no, single or stacked (2) Bt genes for suppression of Lepidopteran feeding were assessed in 2006 and 2007 for boll injury and yield. Each was either treated with additional pyrethroid insecticides or left untreated. A small plot randomized four replicate split plot design was used with pyrethroid treatment as the main plot and variety as the sub plot. Generally, boll damage was greater in non-Bt gene varieties compared with other varieties, and greater in single gene compared with stacked gene varieties. There was no difference in boll damage among the varieties with pyrethroid treatments. Value of pyrethroid treatment was estimated for each variety by comparing product and application cost to lint gain over untreated cotton. Pyrethroid treatments had negative value when applied to stacked gene varieties. Treatments had value when applied to single gene varieties and the greatest value when applied to non-Bt gene varieties.