The purpose of this test was to evaluate the performance of transgenic cotton varieties in Arizona. We conducted four field tests at three Arizona locations in 1999. We included a total of 34 varieties in one or more of these tests. Across locations and varieties, Bollgard (BG) and stacked (BGRR) varieties produced about 7 to 8% greater lint yields than the conventional varieties. Roundup Ready (RR) varieties produced similar lint yields as the conventional varieties. A few transgenic varieties were lower yielding than the conventional parent in these tests. Roundup Ready varieties tended to be taller and more vigorous than the conventional parent. Transgenic varieties were sometimes different from the conventional parent in other traits, such as lint percent, boll weight, or maturity, but the variation was not associated with a particular transgene.