Although most cases of rhinosinusitis are benign, the disruption of quality of life due to disease symptoms leads patients to seek early medical care. Ongoing debates dispute the definition, bacteriology, and medical management of chronic sinusitis, while the criteria for acute sinusitis are relatively well established. Chronic rhinosinusitis remains poorly categorized, and authors differ in opinions of symptoms, time course, and bacteriology of the infections, as well as proper medical management. Recent studies from the Mayo Clinic even question the idea that chronic sinusitis is a bacterial disease and document the presence of fungal pathogens that are responsible for the inflammatory reaction and mucosal response. In general, medical management is based on physiologic principles of re-establishing natural mucociliary function and restoring proper aeration of the paranasal sinuses after an inflammatory insult. Injudicious use and indiscriminate overprescription of antibiotics has fostered the rapid development of penicillin-resistant organisms over the past two decades. Drug-resistant Streptococcus pneumonia and b-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis are becoming the norm, forcing the need to consider alternatives in antibacterial management. Appropriate medical management of this common problem requires a systematic approach and consideration of adjunctive therapy. This article examines the current bacteriology of these common infections and reviews the management of acute and chronic infections.