The importance of South American blastomycosis is proved by about 4,500 evolutive cases, but at present it is still impossible to evaluate the grade of the endemic. Experimental investigations and clinical observations induce to consider that the port of entry ofParacoccidioides brasiliensis is usually pulmonary and that the oropharyngeal lesions are proper of a terminal stage of dissemination and not of primary character. The immunological methods will probably permit an early diagnosis and an adequate evaluation of the endemic. Research in South American blastomycosis needs and deserves the attention of international public health organizations.