The present investigation was carried out at Giza Research Station during 2003/2004 and 2004/2005 growing seasons. All F₁ crosses, including reciprocals, in a diallel mating design among five parents of white lupin differing In origin (Dijon-2, Giza-2, Kereskedeimi, Mutant-23 and Butter Cup) were studied to estimate the genetic components along with combining ability for earliness, seed yield and its components. Significant genotypes mean squares were detected for all traits, indicating genetic variability for all variables. The mean squares of general and specific combining ability were significant for all traits indicating the role of additive and non-additive gene action in the inheritance of these traits. Reciprocal effects were significant for all traits, suggesting maternal effects . Heterosis percentages of F₁ crosses relative to their respective mid and better parents were significantly positive in several crosses for plant height, number of branches, pods, seeds/plant, 100-seed weight and seed yield/plant. Negative heterosis percentage relative to mid and better parents were significant in some crosses for days to maturity. Both parents Butter Cup and Mutant-23 were good combiners for earliness. Dijon-2, Giza-2, Kereskedelmi and Mutant-23 could be superior combiners for number of pods, seed index and seed yield per plant. Moreover, its F₁ crosses recorded high SCA estimates for those traits. The additive component of genetic variability (D) was significant for all traits, except number of branches per plant. H_I values were greater than 0 for number of branches, pods, seeds/plant, 100-seed weight and seed yield/plant, indicating the important role of dominance of genetic variance. Overall degree of dominance (H_i/0)^1/2 was less than unity for days to maturity and plant height, indicating partial dominance for these traits. The estimates of Ko/Kr, were greater than one for plant height and seed index, which indicated an excess of dominant genes in the parents. The heritability values in broad sense were moderate for number of branches per plant and high for the other traits. However, narrow sense heritability estimates were relatively high for days to maturity and plant height, moderate for number of pods, seeds/plant, seed index and seed yield/plant, and low for number of branches per plant.