Breeders are aware of the phenomenon that in a hybridization programmes, certain crosses pass-on more favorable genes towards the progenies than others. Thus, identification of potential parents and hybrids remained main concern to cotton breeders for improving various yield and fibre traits in cotton breeding programmes. The present studies were carried-out to estimate the general and specific combining ability estimates and heterotic effects for different characters from line x tester crosses developed from six lines viz., Sindh-1, Sadori, CRIS-134, Chandi-95, Haridost and IR-1524 crossed with three testers i.e. NIA-ufaq, Sohni and Shahbaz. The experiment was laid-out in a Randomized Complete Block Design with four replications during 2016. The degrees of freedom for hybrids were split into lines, testers and line x tester interaction. The mean squares owing to lines and testers were significant for majority of the traits, however the general combining ability of lines for 1st sympodial node number while general combining ability of testers only boll weight was non-significant. Similarly, the mean square for line x tester interaction which designate specific combining ability were also significant for all traits except staple length, G.O.T. % and seed index. Among the lines, Chandi-95, IR-1524 and from testers Shahbaz expressed higher GCA effects especially for seed cotton yield, thus, proved as good general combiners and suitable parents for hybridization and selection of desirable plants from segregating populations. For SCA effects, F1 hybrids like Sadori x Shahbaz, Haridost x NIA-ufaq and Sindh-1 x Shahbaz demonstrated as best specific combiners, therefore’ these proved promising hybrids. The high heterotic effects were expressed by the hybrids Sadori x Shahbaz for bolls per plant, boll weight and seed cotton yield plant-1 and IR-1524 x NIA-ufaq for staple length thus, these hybrids with dominant and over dominant genes could be potential hybrids for the exploitation of heterosis breeding in cotton.