The Multi-Adversity Resistance (MAR) program has developed five MAR hybrid pools which have produced cotton cultivars having a progressive improvement in resistance to plant pathogens and insects, lint yield and fiber quality. Field experiments were conducted in 1988 and 1989 at College station, Temple and McGregor to determine the genetic gains in yield, earliness and fiber quality achieved in each hybrid pool. The MAR cultivars evaluated in the study were Tamcots SP21 and SP37 (MAR-1), Tamcots CAMD-E and SP37H (MAR-2), MARCDPS-1-77 (MAR-3), Tamcots CD3H and CAB-CS (MAR-4) and Tamcot HQ95 (MAR-5). Results indicated that there have been genetic gains achieved in the MAR germplasm, from MAR-1 to MAR-5, in lint yield, earliness, and fiber quality, especially in fiber length and strength. These gains parallel the increases in levels of resistance to insects. A 25% increase in total yield and a 37% increase in earliness was observed from the MAR-1 to MAR-5 populations.