Arabidopsis Cor15am is a late embryogenesis abundant (LEA) related protein that has been shown to exhibit cryoprotective activity in vitro. In this study, we further investigated the mechanisms by which Cor15am protects substrates from inactivation. Although Cor15am did not exhibit refolding activity, it showed protective activity against various stresses in vitro. This might be attributable to the activity of Cor15am in attenuating the aggregation of the substrates. Our data indicate that Cor15am functions as a protectant against various stresses by preventing protein aggregation.