Seeds of the single hibrid mayze BR 201 were harvested in intervals of seven days from 35 to 84 days after flowering, to study the physiological maturity of seeds. The following parameters were evaluated: seed moisture content dry matter acumulation by the seed, black layer formation, germination and vigor. The physiological maturity, based on dry matter acumulation of the seeds of the female line of the hibrid BR 201 occured in 65 days after flowering. To obtain seeds of high quality, harvest can be started at 55 days after flowering when the seeds already reached around 87% germination, 82% of vigor and 95% of seed with black Iayer.