Soybean (Glycine max (L.) Merrill) seeds, cvs "UFV-1" and "Paraná" were divided into two size classes using for this oblong hole screens, the perforations with the following sizes: 9/64 x 3/4 and 13/64 x 3/4. A third unclassified portion was used. Those seeds were artificially aged under conditions of 43oC and 100% R.H. for 0, 18 and 36 hours. The effects of those treatment-combinations were measured in terms of seedling total emergence, speed of emergence and dry matter content. The results obtained showed some inconsistencies: while seedling total emergence did not show any effect of seed size on seed storage potential, speed of emergence and dry matter content did, in the sense that there would exist a direct relationship between seed size and seed storage potential: the larger the seed, the larger its storability. A strong variety effect was also observed.