The deficit of storage capacity along with the increasing production has forced producers of northern Mato Grosso, Brazil to store the corn outside of the conventional silos. Therefore some producers have searched looked for alternatives, such as silo bags. However there are many questions about the behavior of grains in this system. With the objective of monitoring the grain condition during storage of corn, a silo bag was instrumented with temperature sensors, in nine points, connected to a data logger. The product was stored for a period of four months. Samples were collected periodically for the purposes of moisture and grain quality evaluation. The following parameters were evaluated: bulk density, mass of 1,000 kernels, germination, accelerated aging, and levels of protein and oil. Results showed that the temperature of the grain mass was constant during the storage period, without influence of the variation of the external temperature. The equilibrium moisture content of the corn was computed based on empirical equations considering the ambient conditions. It was found that if the product was subjected to aeration, the possibility of moisture reductions to below 10% w.b. could be significant. The corn moisture remained on average 11.2% w.b. with a coefficient of variation of 2.7% except for the month of October where moisture decreased to 10.4% w.b. There were no significant changes in the percentage of germination, the values of bulk density, mass of 1,000 grains and oil content, during storage.