Gene action and components of variance analysis were made in a 6X6 diallel cross in durum wheat (Triticum durum Desf.). Additive gene effects were more important for all the traits. Complete dominance for yield plant-1 and spike length and over dominance for tillers plant-1 was observed. While plant height, spikelets spike-1, grains spike-1 and 1000-grain weight exhibited partial dominance. Dominant alleles were more frequent in parents for all characters except plant height and 1000-grain weight. Durum wheat genotypes, Altar 84 and Bittern "s" showed relatively higher combining ability.