This paper compares the profitability and cost of production of irrigated Roundup Ready^® cotton varieties and conventional cotton varieties grown under crop share rental agreements in the Texas High Plains Region for 1998. The Standardized Performance Analysis (SPA) program was used to analyze 25 sub-enterprises for each variety type from six producers selected from the regional SPA database for 1998. The results indicate that the Roundup Ready^® cotton varieties were more profitable with returns to operator labor, management and risk of $72.55/acre versus $58.93/acre for conventional cotton varieties. Weed control and seed cost for the Roundup Ready^® cotton varieties was $11.79/acre greater than for the conventional varieties. The increased profitability for the Roundup Ready^® cotton resulted from higher lint yields.