The experiment was carried out from May 1992 until May 1993, at the Federal University of Viçosa, MG, Brazil. A completely randomized design was used, with onion (Allium cepa L.) seeds (cv. Pira Ouro), with 6% humidity, conditioned in six types of packagings (Cloth, PVC within Paper PVCP, Rigid Polyetilene-RP, Flexible Polyetilene-FP, Flexible Alumunized-FAL and Can), with four replications. The seeds were placed on three environments of storage (20oC and 50% RH, Laboratory environment, 30oC and 80% RH) during five periods of storage (0, 3, 6, 9 and 12 months), with objective of identify the more efficient and lower cost form for storage onion seeds. Seed vigour was not affected at 20oC and 50% RH. At the laboratory environment, the reduction in seed vigour was observed after the sixth month in Cloth and PVCP. Seed stored at temperature of 30°C and 80% RH, reduced the vigour after three in PVCP, RP and FP. The packagings FAL and Can did not alter the vigour during the experimental period. The differences in performance in the diverses packagings were atributed to the increase of seeds humidity into. the permeable packagings and to the degree of hygroscopic equilibrium between seeds storage environment.