One hundred and fifty immunocompetent and 150 presumably immunocompromised patients suffering from lower respiratory tract infections were enrolled in this study. The clinical specimens were collected from April 2007 to June 2008 and included sputum (247), bronchial wash (80), and blood (300) samples. The identification process employed direct examination, culture, conversion test, and serological study. Among 218 fungal isolates only six were categorized as true pathogenic fungi; two Histoplasma capsulatum, and four Blastomyces dermatitidis. The former isolates were detected in two immunocompromised patients, while the latter isolates were detected in two immunocompetent and two immunocompromised patients.