The present investigation was carried out during growing seasons 2016-2017 and 2017-2018 at Field Crops Department, College of Agricultural Engineering Sciences, University of Duhok-Iraq, using five genotypes of Faba bean using half-diallel mating crosses according Randomized Complete Block Design (RCBD) with three replications to study combining ability ,gene action and heterosis for yield and its related component traits, the analysis of variance founded to be highly significant mean square for all studied traits. General combining ability and specific combining ability mean squares were highly significant for all tested traits. The results showed that parents Po6-oo3FB and Po6-oo9 FB were the best general combiners, crosses Po6-oo3FB x Po6-oo9FB and Po6-oo3FB x Po6-o13FB exhibited significant specific combining ability effects for most of traits, crosses Po6-oo3FB x Po6-oo9FB, Po6-oo3FB x Po6-o13FB and Po6-oo9FB x Po6-o13FB showed the best heterosis over mid- parent and better parents in desirable direction for studied traits, broad sense heritabilities ( h2.B.S.) were high for all traits, indicated that small effect of environmental conditions on inheritance of these traits , and hence suggested that the traits improvement can be obtained through selection methods of breeding.