Eucalyptus pellita seeds have a very small size, so that it needed techniques of seed sorting using sieves to increase quality of the physical and the physiological. This study aims to determine sieve size for sorting seeds of E. pellita so as to maintain viability. E. pellita seeds used in this study comes from seedling seed orchard (KBS) in southern Sumatra, South Kalimantan, and Riau. Seed sorting is done with some sieve size namely 200 µm, 400 µm, and 600 µm. Parameters measured were the purity, weight of 1000 grain seeds, and germination. The results showed that the size of a 600 µm of sieve is appropriate for sorting seeds E.Pellita, because it can result in weight of 1000 grains (0.0362 grams), purity (60.54%) and higher germination percentage (184 sprouts/0.1 grams) than the others.