A 7-month-old girl with persistent fever that did not respond to antibiotics was found to have a yeast infection in her blood through examination of a blood sample under a microscope. This discovery was unusual because such infections are typically difficult to spot without special culture tests. After treatment with the antifungal medication fluconazole, the child recovered completely. This case shows how simple microscopy can help diagnose serious fungal infections in areas where advanced laboratory testing is not available.