Rhinosinusitis is a common illness that represents a substantial economic burden. The vast majority of cases resolve spontaneously but a small proportion develops a secondary bacterial infection. Accurate diagnosis of rhinosinusitis depends upon clinical assessment. Isolation of the causative agents must be considered in cases failing initial treatment.This up-to-date review defines the anatomy, pathogenesis, phases of rhinosinusitis, the unique microbiology of each type of rhinosnusitis (acute and chronic, acute exacerbation, nosocomial, rhinosinusitis in immunocompromised host, and rhinosinusitis of ododental origin), clinical features, diagnosis, and treatment.The reader will gain understanding of the above issues and logic for choosing the appropriate treatment for each condition of rhinosinusitis.The proper choice of antibiotic therapy depends on the probable infecting pathogens, bacterial antibiotic resistance and antibiotics' pharmacologic profiles. In addition to antibiotics, adjuvant therapies and surgery are used in the management of bacterial sinusitis. Accurate diagnosis and careful consideration when choosing therapy for rhinosinusitis will optimize the chances of achieving an early recovery and avoiding complications.