Radiological investigations are essential for the diagnosis and classification of fungal rhinosinusitis; however, radiological findings might occasionally be misleading. Computed tomography (CT) scan and magnetic resonance imaging (MRI) complement each other, facilitating clinicians to arrive at a diagnosis. Hence, even with the best radiological modalities, correlation between clinical and microbiological findings is crucial for the accurate diagnosis of fungal rhinosinusitis. In addition, the role of traditional methods such as KOH microscopy and culture should be accurately evaluated. To this end, we aimed to diagnose rhinosinusitis with a fungal etiology based on radiological findings and subsequently correlate these findings with those of microbiological techniques, namely culture and KOH microscopy. A total of 57 clinically suspected fungal rhinosinusitis cases were included in the study. Radiological investigations were performed using either CT or MRI. Tissues samples were processed and analyzed using KOH microscopy and culture. The results of the study suggest that using a single method for the diagnosis of fungal rhinosinusitis is inadequate. Rather, the diagnosis should be based on radiological as well as microbiological findings, especially for cases that are clinically ambiguous.