Cotton production in Burkina Faso regularly suffers from significant pest damage. Conventional pest control measures have failed to adequately control the main cotton pest, Helicoverpa armigera. Burkina Faso began testing of genetically modified (GM) cotton in 2003 to assess the efficacy of the Bollgard II (BII) genes in controlling Lepidoptera pests. Field trials were conducted at two agricultural research centers in Burkina Faso (Farako-Bâ and Kouaré). The field trials compared conventional cotton varieties to GM cotton varieties in order to estimate the effectiveness of the BII genes in protecting cotton plants and improving cotton yields. The field trial results found that Bollgard II cotton would increase cotton yields by as much as 38% compared to conventional cotton. Significant differences in yield gains were found between the two sites, with higher yield gains reported at Farako-Bâ. An economic simulation model found that BII cotton would increase farm income in the range of $35 to $110 per hectare depending on the seed price.