We believe there is strong evidence to support a continuing search for coccidioidomycosis in new areas, in the Old World as well as in the New World, and in places with a climate and ecology different from the semi-arid conditions of the known endemic areas. Such an investigation would be justified in any population group where there is a high incidence of respiratory disease of unknown etiology. Very satisfactory and practical immunological techniques are available, but the present evidence indicates that the antigens used in these tests should be prepared from strains ofC. immitis recovered from the area to be investigated. Obviously this cannot be done at present, so such a program should be preceeded by an extensive survey of soil samples in the area in order to recover any existing native strains ofC. immitis. Whereas this would be the ideal situation, one could consider initiating the proposed study with coccidioidins prepared from selected strains of this fungus, incorporating as complete a spectrum of known antigens as is possible with our present knowledge, and keeping in mind that even this may not be adequate. We would welcome the opportunity to assist any investigator preparing to undertake a survey for coccidioidomycosis in his country.