BACKGROUND Histoplasmosis is a fungal disease caused by Histoplasma capsulatum. Histoplasma capsulatum var capsulatum is found in Martinique. Cluster cases following working in deserted house, have been described in Martinique. Cases of acute pulmonary histoplasmosis have been described in immunosuppressed individuals, or in case of substantial exposure to reservoirs of Histoplasma capsulatum; however, cases of acute histoplasmosis are rare in immunocompetent individuals. METHODS We report a series of 4 cases of sporadic acute pulmonary histoplasmosis in immunocompetent subjects. Investigation revealed definite exposure in one patient and 3 cases with potential exposure. The diagnosis was microbiological and histological in 3 patients and histological in one patient. All subjects had positive serology to histoplasmosis. Pulmonary involvement was in the form of nodules and micronodules in 3 cases and ground glass lesions in one case. Patients were treated with itraconazole for 3 months and all had a favourable outcome. CONCLUSIONS We report a series of 4 cases of acute pulmonary histoplasmosis in immunocompetent individuals, occurring in a context where exposure was uncertain. This raises the problem of occult exposure in the Caribbean. Interventions to raise awareness and encourage caution are warranted targeting the population of the French West Indies and French Guiana.