Activities of acid and neutral alpha-glucosidases (EC 3.2.1.3 and EC 3.2.1.20, respectively) were compared in human lymphocytes and granulocytes. As shown by means of antibodies to acid alpha-glucosidase, this enzyme prevailed in lymphocytes while in granulocytes it constituted only a slight part of the total alpha-glucosidase activity. Neutral alpha-glucosidases of both these cells were distinctly dissimilar. Neutral alpha-glucosidase from granulocytes exhibited more wide pH optimum as compared with the lymphocyte enzyme, at the same time, the granulocyte enzyme was stable at pH 4.0, 37 degrees, 15 min and was inhibited by turanose. The data obtained suggest that granulocyte neutral alpha-glucosidase was similar to the same enzyme from kidney, whereas lymphocyte neutral alpha-glucosidase--to the enzyme from liver tissue.