A method of antigen preparation from Aspergillus fumigatus has been described. We received the antigens from medium and mycel used for the detection of precipitins and IgE-antibodies. The antigenic components are demonstrated in the immunoelectrophoresis. By the use of absorption we did not find essential differences between medium antigen and mycel antigen for the detection of precipitins. The medium antigen recommended for diagnostic is easier to produce and, moreover, has advantages for the detection of specific IgE antibodies.