The hypothesis that fungus causes most, if not all, cases of chronic rhinosinusitis (CRS) has been debated for over a decade. Many opinions and interpretations have been rendered, but it is the objective data that speaks the loudest. The debate simply boils down to a core tenet of the scientific method: Can the data be independently replicated? If so, our patients benefit as new treatments are developed. If not, then the hypothesis must be discarded and new lines of research pursued. Initial clinical trials supporting the fungal hypothesis have not been replicated in recent years by independent investigators. An attempt to independently replicate the basic science foundation of this hypothesis has also failed in a more heterogeneous group of CRS patients. The data can be dissected, reanalyzed, and reinterpreted and myriad arguments can be put forth. But an unbiased review of the data demonstrates that nearly every researcher outside of the original proponents of the fungal hypothesis has failed to replicate their work. The weight of the evidence is increasingly tipping the scales away from this theory.