The effect of particle size distribution of alumina has been investigated for silica-free tabular alumina low cement castables (LCC). Three different combinations of alumina have been included in the matrix formulation of the castables. All the three combinations are composed of a bimodal reactive alumina and a fine ground monomodal reactive alumina. The first A1 and second A2 combinations are respectively composed of bimodal and monomodal aluminas from Alteo, with a different fine/coarse particles ratio for the bimodal alumina. The two Alteo combinations have been compared with a third combination C composed of a bimodal commercially available grade and a monomodal commercially available grade. Optimization of particle size packing has been performed for the three different formulations using the Dinger and Funk model. With this optimization, the two formulations based on Alteo material (PFR, PBR and PFR40) achieve the same level of performance in applicative tests (flowability, cold physical properties, mechanical resistance, crystalline phases, thermal shocks and corrosion) as reference solutions on the market.