The present study was carried out in inter-specific cotton hybrids of G. hirsutum x G. barbadense to evaluate the extent of heterosis and combining ability for eight yield and fibre contributing traits. Twenty four interspecific hybrids derived from four different lines of G. hirsutum and six testers of G. barbadense were assessed for various parameters. Significant heterosis was recorded for the traits under study suggesting that the existence of genetic diversity among parental lines. The hybrid CO16 x RHCB 1014 exhibited significant positive standard heterosis for seed cotton yield per plant followed by CO15 x TCB26 and SVPR6 x DB1602. The hybrid CO15 x CO18 was the best for the number of bolls per plant, plant height and ginning outturn, while, SVPR6 x DB1602 was the best for UHML and bundle strength. Combining ability analysis exhibits the non-additive gene action in all yield contributing and fibre quality traits. The three lines viz. CO16, MCU7, SVPR 6 and four testers viz.TCB26, DB1602, CCB 143B and CO18 were noted as the best combiners. The hybrids CO16 x CCB 143B, CO16 x DB1601, CO15 x TCB26 and SVPR6 x DB1602 were identified as the best specific combiners and are suggested for advanced breeding programs. Key words: Cotton, interspecific hybrids, heterosis, combining ability.