The paper presents the analysis of the influence of water content on the relative activity of spray-dried alpha-arnylase (Aspergillits oryzae). The enzyme dissolved in a maltodextrin solution was spray-dried at various air temperatures and feed rates: The water content in powders and relative enzyme activity after the process of drying was determined. The relative enzyme activity was strongly related to water content, which depended on the outlet air temperature. The optimal final water content in respect to the enzyme activity should vary from 0.07 to 0.09 g H2O/g db.