The objective of this work was to compare oven methods for determining seed moisture content of five species, using the oven method 105°C for 25 hours. Other comparison methods were 130°C/4 hours (milled seed) for corn; 130° C/2 hours for wheat and rice (milled seed); 103°C/17 hours for soybean and onion. Onion seeds were not milled. Seeds showed the following initial moisture content percentages: 10.5 and 18.0% (soybean); 12.0 and 18.0% (onion); 11.0, 14.0 and 18.0% (corm); 13.0, 14.0 and 19.0% (wheat); 12.0, 14.5 and 18.0% (rice). The results shoewd that for wheat and rice seeds, 105°C/24 hours presented for alI initial moisture content leveIs, the lowest moisture content. For soybean and onion there were differences in determining the moisture content between both methods (105°C/24 hours and 103°C/17 hours) with seeds of moisture content of 18.0 and 19.0%. Otherwise, for corn seeds, only were showed up differences at the moisture content of 11.0%. lt can be concluded that there were differences in the moisture content determination by the oven method for all species studied the differences in the results varied according to the species and the initial moisture content.