In the immunocompromised host, uncommon pathogens have been documented as causing sinusitis. Resistance to standard antibiotics for sinusitis in the immunocompromised individual must prompt nasal culture and biopsy for early diagnosis. Immunocompromised host include neutropenic patients, Human Immuno-Deficiency (HIV) infected patients and non-HIV-suppressed patients. Unusual bacterial organisms (Pseudomonas Aeruginosa), mycobacteria, fungi (Aspergillosis) and viral infection (Cytomegalovirus) have all been found to cause sinusitis in immunocompromised patients. Early detection of these infections with appropriate anti-infective agents associated with radical or functional endoscopic surgery seems to be the optimal treatment. Recovery of immunity remains the major prognostic factor.