Three agar immunoprecipitin techniques (double immunodiffusion, immunoelectrophoresis and immunoelectroosmophoresis-immunodiffusion) made with paracoccidioidin and serum of a paracoccidioidomycosis patient's wife, permitted us to observe a specific band in 6 successive samples of blood taken from the wife over a period of 21 months. The case represents an example of a subclinical paracoccidioidomycosis infection that is usually diagnosed in its disseminated, progressive form. Three possible sources of infection are discussed. But an interhuman contagion appears to be the most feasible.