The present study was made in upland cotton with 10 x 10 half diallel to assess the extent of heterosis over standard check (LAHH 5) for seed cotton yield and its related traits at Regional Agricultural Research Station, Lam, Guntur. The highest heterotic effect were recorded in the hybrids SCS-1207 × GSHV-177, GSHV-177 × L1231 and SCS-1207 × PBH-13 were promising hybrids in this study over the standard check for seed cotton yield per plant and its most of the yield attributing traits. Those hybrids exhibiting high heterosis for seed cotton yield per plant also had high heterosis for yield attributing characters. The study reveals good scope for commercial exploitation of heterosis as well as isolation of pure lines among the progenies of other heterotic F1 hybrids.