The main objective of this work was to evaluate the influence of mechanical damages, during seed processing on the phisiological quality of two cultivars of soybean seed. Eleven seed samples were drawn along the seed processing line. The following parameters of seed quality were evaluated: seed water content, germination, mechanical damage (by chlorox soak test and the tetrazolium test), vigor (tetrazolium, accelerated aging, eletrical conductivity, field emergence, and seedling growth rate tests). Comparing seed quality from both cultivars, Paiaguás showd a lower percentage of injuried seeds and a superior seed quality than Dourados?seeds. For both cultivars it was observed a reduction in seed quality related to germination and vigor during proceessing and handling, when compared the hand harvested seeds samples. Results allowed for the following conclusions: depending on the original quality of the seed lot, it may be irnproved by processing operations; mechanical damage may occur along the processing une and it is cumulative; there is a different response of cultivar to mechanical damage, what may be attributed to genetic variability occurring in soybean germoplasm. Results of this research work suggest that: studies should be conducted to improve the efficiency of seed processing equipment. The equipment sequence and also the seed flow along the processing line should be studied to improve seed quality by reducing the mechanical damage on this operations.