Present study was conducted during 2013-14 at University of Agricultural, Faisalabad, Pakistan to Fig. out gene action and heritability of lint yield and quality traits in upland cotton. Parental genotypes viz COKER-3113, CRIS-9, BT-122 and CRS-456 were crossed following 4×4 diallelmating design. Genotypes showed significant variations for plant height, monopodia plant -1 , sympodia plant -1 , bolls sympodia -1 , bolls plant -1 , seed cotton yield plant -1 , fiber length, fiber fineness and fiber strength. On an average, the combinations showed boost over parents for plant height (10.5%), sympodia plant -1 (7.04%), bolls sympodia -1 (3.73%)and seed cotton yield plant -1 (24.07%). Broad sense heritability coupled with higher response to selection was plant height (0.95 and 17.85 cm), monopodia plant-1 (0.75 and 0.39), sympodia plant-1 (0.82 and 3.46), bolls plant-1 (0.89 and 8.95), boll weight (0.93 and 4.43g), yield plant-1 (0.72 and 39.00 g), fiber fineness (0.79 and 0.33), fiber length (0.87 and 0.39), fiber uniformity (0.78 and 0.34), fiber strength (0.67and 0.29) and fiber elongation (0.89 and 0.42).Parents CRIS-9 and COKER-3113 performed better in their specific cross combinations and showed significant mean performance. The crosses CRIS-9 × COKER-3113, CRS-456 × CRIS-9 and CRS-456 × CRS-456 showed genetic potential for almost all the traits. Findings suggested that the above three crosses should be used in cotton breeding programmes and selection may be done in late segregating generations for further improvement in lint yield and quality.