A process for the production of yogurt powder possessing an immunological activity, in which yogurt is heated at 60 DEG to 100 DEG C. and it is provided with an alkaline agent to adjust the yogurt to pH 7.0 to 96, and thereafter dried to a powder. Before powdering, the yogurt may be subjected either to the addition of a non-ionic surfactant or to high pressure homogenizing treatment. Yogurt retaining immunological activity can be used effectively as food and feed.