This is a case of a 53 year old woman, non-smoker, presenting with a history of grade III/IV shortness of breath, gradually aggravated over the last week. The patient reported a history of idiopathic pericarditis, diagnosed 4 months ago, under treatment with methyl-prednisolone (24mg/daily). Her clinical examination was unremarkable, while her laboratory findings were indicative of normochromic normocytic anemia (Hct 35%) and lymphopenia (WBC:9.89: Neu:70.2%, Ly:11.5%, MO:3.5%, Eo:1%, Ba:0.1%). Chest x-ray revealed diffuse non-homogeneous opacities of alveolar type, and confluent nodules especially in the middle and lower lung zones. HRCT revealed a predominantly nodular appearance with nodes and nodules in contact with broncho-vascular structures, as well as greater areas of consolidation (possibly due to confluence of pulmonary nodules). Branched linear and nodular opacities, and a patchy ground glass pattern were also noted. Microbiology, virology and immunology testing turned up negative. Despite provided therapy with conventional antibiotics the patient.s clinical condition rapidly deteriorated. The patient underwent bronchoscopy and bronchoalveolar lavage (BAL), whose culture was positive for Penicillium Marneffei (greater than 106). The patient was thereafter administered Amphotericin B and Itraconazole, resulting to a temporary improvement of her clinical condition and radiological findings. Unfortunately the patient died 20 days following the initiation of the indicated therapy. Pneumonia due to Penicillium Marneffei is an extremely rare condition and few references exist in international medical literature. Pneumon 2006, 19(1):74-80.