Fungal pneumonias are rare but important. Sometimes the clinical presentation is identical to more common bacterial or atypical pneumonias. In such cases, the diagnosis is either not made or is made accidentally from diagnostic specimens obtained to determine the likely bacterial pathogen. Other cases look like routine bacterial or atypical pneumonia at presentation but do not improve or even progress as they are being treated with appropriate antibacterial agents. In such cases, it is important not to give a series of treatment courses with different antibacterial antibiotics that all cover essentially the same range of pathogens. Rather the diagnostic efforts must be escalated, progressing to more aggressive measures (fiberoptic bronchoscopy, fine needle aspiration, and rarely thoracoscopic or traditional open lung biopsy) until a specific diagnosis is reached. In some cases, there are clinical clues that point to a fungal cause. Attention to these clues can lead to early initiation of appropriate diagnostic sequences, faster diagnosis, and earlier initiation of specific therapy. A review of some of these clinical clues is provided in Table 1.