To determine the ideal time of harvesting soybean seeds (Glycine max (L.). Merrill), were made with Davis and Bossier cultivars. The two cultivars were manually harvested in four different times, with one additional treatment mechanically harvested. For the Davis cultivar, harvesting was made each seven days, beginning at 44% of moisture, and the mechanical harvesting was made at the some time as the last manual harvesting. For the Bossier cultivar, harvesting was also made each seven days, beginning at 16% of moisture, and the mechanical harvesting was made at some time as the second manual harvesting. In both experiments the germination was determined each month of storage, and the end of this period the seeds were submitted to the tetrazolium test, to determine vigour and germination capacity. Seeds of Davis cultivar presented low germination rates after each storage period in all harvesting times. The Bossier cultivar presented best quality seeds in the first and second harvesting times.