Cotton (Gossypium hirsutum L.) seeds from the varieties IAC-20 RR, CS-50, DP20, DP-90 A and DP-90 B acid-delinted were stored during 12 months, under environment conditions. The seed quality was evaluated before storage and at each three months, by using the following tests: germination, accelerated aging, cool germination, electrical conductivity and health. It was observed that the increase of storage period seeds provided linear decrease of viability and vigor of seeds, and linear increase of incident storage fungi. The cool germination indicated efficient for evaluate the seeds vigor during storage, indicated stratify better of lots in vigor levels than accelerated aging test.