Five genotypes of melon were obtained from Cornell University named, Line 00-1107 (P₁); Line 00-1102 (P₂); Line 00-1117 (P₃); Line 00-1109A (P₄) and Line 00-1113 (P₅) which crossed in a half diallel mating design in Kaha Research Farm, Horticultural Research Institute, Agriculture Research Centre in the Kalyobiya Governorate, Egypt, during the planting summer seasons 2021 and all genotypes were evaluated during 2022 season. The results indicated that the genotypes in the study possessed high variability for all the studied traits. There were high differences between the crosses for mid parent and better parent heterosis in all the studied traits. F₁ hybrids (P₃×P₄) and (P₄×P₅) gave the highest means for yield and yield attributes. The magnitudes of GCA and SCA effects were significantly which indicated the presence of both additive and dominance gene effect in governing all the studied traits. The GCA/SCA ratio was more than one which indicates that additive gene effect was more important in the inheritance of the studied traits. General combining ability analysis exhibited that P₃ and P₄ could be considered as promising parents in breeding programs to produce melon hybrids. Heritability in the broad sense was larger in values than their corresponding heritability in narrow sense, which indicates the large effects of the genetic variance on the expression of these traits. The obtained results of heritability evaluation presented additional evidence about predominance of dominance gene effect in the inheritance of the studied traits. Therefore, hybridization program could be used for producing superior promising melon hybrids.