Bacterial blight of cotton is a major foliar disease caused by Xanthomonas campestris pv malvacearum (Xcm) resulting in leaf defoliation. The multi-adversity resistance (MAR) program is active in developing cultivars having high resistance to the known USA races of the pathogen. The program maintains races of Xcm and a host differential set of Upland cotton for race identification. Intense selection for resistance to the bacterial blight pathogen begins in the F₁ through the F₄ generation utilizing laboratory and field inoculation and screening procedures. Details of the methods used by the MAR program in developing cultivars resistant to the bacterial blight pathogen are discussed. High resistance to bacterial blight is available in several cultivars and germplasms.