The activity and expression of diamine oxidase during the germination of lentil seeds and in the course of anoxic and thermal stress have been studied. Diamine oxidase activity, as well as the seedlings growth rate, was found to be markedly higher in dark-grown lentil seedlings than in the light-grown ones. The same was true for the respective protein and mRNA amounts. The specific activity of diamine oxidase was decreased by anoxic stress and not affected by thermal stress. The possible physiological meaning of these findings is discussed.