The purpose of this report is to describe the results of a prospective study on pulmonary histoplasmosis in French Guiana. Chest radiographs were performed in 232 French legionnaires returning from a two-year assignment in French Guiana. Further examinations were performed in a total of 8 subjects in whom chest radiographs demonstrated the presence of nodules in the lungs. No evidence of cancer or tuberculosis was found. Findings confirmed histoplasmomas in two cases and demonstrated probable histoplasmosis nodules in 6 cases including three involving calcified lesions. Five of these eight patients had been in high-risk rain forest environments. Pulmonary histoplasmosis should be considered as a possible diagnosis in subjects returning from endemic zones. Confirmation depends on a spectrum of findings. Calcified nodules require only radiographic surveillance with follow-up at six months. Non-calcified nodules require further investigation including CT-scan, bronchoscopy, and serological tests. Surgical biopsy may be necessary to achieve exact histological and mycological identification of the lesion and is recommended in smokers.