Conducted the breeding researches with interspecific cotton crosses are aimed to obtain genotypes have desired fiber characteristics like Gossypium barbadense L. and have high yields potential like Gossypium hirsutum L.. In this study, gene action and useful heterosis were investigated for fiber quality and yield traits in interspecific cotton crosses. The 12 F1’s and their parents were evaluated in a Randomized Complete Block Design with four replications at the Nazilli Cotton Research Institute’s fields during 2011 and 2012 cotton growing season. Claudia, Candia, Sahin 2000, BA 308, Naz 07 and Fantom (Gossypium hirsutum L.) were used as a female parents and Giza 45 and Avesto (Gossypium barbadense L.) used as a male parents. Non-additive gene effects for yields, fiber strength and fiber length were greater than additive gene effects. The useful heterosis were positively significant for fiber strength and fiber length. Candia x Giza 45 hybrid was promising hybrid for all observed characters.