The influence of hydration-dehydration process upon soybean seed physiological quality was detected after different storage periods, using UFV 10 (Uberaba), IAC 8 and Doko RC varieties. Initially, the seeds were osmoconditioned in a polyethylene glycol (PEG 6000) -0,8MPa solution, at 20°C, for a period of four days. The seeds were dried back until reaching the initial moisture content (10-11%) and afterwards they were stored in natural conditions for three and six months. Two controls were used: untreated seeds (dry seeds) and water soaked seeds for a sufficient period to reach the same moisture content of the osmoconditioned seeds and, than, dried back. After the storage periods the seeds were evaluated by the standard germination test (first and final count), seedling length and dry matter weight of seedlings, speed of emergence-index and final emergence in sand seedbed. The hydration-dehydration process was effective in increasing the germination percentage of soybean seeds and efficient in maintaining the seed physiological quality during the storage period, as well the benefits from osmoconditioning were maintained after soybean seed dehydration. The water soaking, followed by drying, was deleterious to seed quality. The hydrationdehydration treatment increased the percentage of emergence, favoring faster and more uniform seedling establishment, after a relative extended seed storage period.