During the maturation and harvest of soybean (Glycine max (L.) Merr.) seed the ideal climatic conditions include dryness and lower temperatures. Using winter-sown (July to September) soybean we verified the effects of irrigation on the physiological quality of soybean seeds during maturity using a factorial treatment design with three varieties (IAC-19, Conquista and IAC 8-2) and two irrigation interruption times (starting at stage R 7 and irrigating until 14 days after stage R 8). The samples were taken at stage R 7 and at 3 days, 7 days, 10 days, 14 days (stage R 8) and 28 days after starting stage R 7. We evaluated the percentage germination, vigor using accelerated aging and electric conductivity tests, and the percentage of spotted and imperfect seeds and found that irrigation after stage R 7 does not reduce seed quality but can improve the physiological potential of the seeds.