A half diallel set including diverse five parental peanut genotypes was evaluated at Ismailia Agricultural Research Station, ARC,Ismailia Governorate,Egypt using randomized complete block design with three replications to estimate mean performance,combining ability,heterosis and nature of gene action.Highly significant genotypes and its components of parents,crosses and parents vs.crosses mean squares were detected for all studied traits.Highly significance of general and specific combining ability was observed for all studied traits.Additive gene action governed in plant height, number of pods/plant, number of seeds/plant,100-pod weight and shelling %. Ismalia 2,Line 360 and Giza 6 seemed to be the best combiners for pod yield /feddan and most of its components.The best cross combinations were detected in F₁ crosses, P2 ×P3 for seed weight /plant and P3 × P5 and P4 × P5 for pod yield / feddan.Significant or highly significant values and high values of the dominance component (H₁) were also observed for the most studied traits. P5 carried the most dominant genes responsible for the expression of seed weight/plant and pod yield / feddan, while, P4 for seed weight / plant and P1 and P2 for pod yield / feddan possessed high concentration of recessive genes. It could be concluded that, Ismalia2, Line 360 and Giza6 could be used as donors parents to improve yield and its components of peanut in the breeding program,also, the crosses P2 ×P3 ,  P3 × P5 and P4 × P5 with high SCA may  be  exploited  for  the  development  of hybrids  as they  had  high  per  se performance.