Three promising strains Extra long staple cotton genotypes were evaluated compared with the four commercial cultivars grown in five different locations in Lower Egypt during the two successive seasons 2009 and 2010. Randomized complete block design with four replications was used at each location. The traits studied were seed cotton yield, lint yield, boll weight, lint percentage, seed index, lint index, fiber length, fiber strength and micronaire reading. Highly significant differences between genotypes, locations, seasons and the interaction between locations by seasons were obtained for yield, yield components and fiber quality properties. The effect of the interaction between genotypes by locations was highly significant for all traits except, seed index and lint index, but the interaction between genotypes by seasons and the second interaction were significant for all traits except, seed index. The results showed that the two promising strains [G.84 (G. 70 × G. 51 b)] × Pima 62 and G.88 (G.68 × G.45) produced the highest values for yield and most yield components traits than the other cultivars. However the promising strain (G.77 × S6) had the highest fiber length and fineness. From the results, the promising strain (Giza 77 × S6) exceeded the commercial cultivar Giza 87 in fineness at three locations (Kafr El-Sheikh, El-Dakahlia and Damiatta) regions. Adaptation to different environments was high in the promising strain (Giza 77 × S6) at El-Beheira region for most characters. The promising strains [G.84 (G.70 X G 51b)] × Pima 62 and G.88 (G.68 × G.45) produced the highest values than the commercial cultivars Giza 70 and Giza 88 for yield, most yield components and fiber properties at El-Dakahlia region. Therefore, it seems necessary to continue evaluating new cotton genotypes by growing them at several locations over an adequate number of years before recommending any variety for a certain location.