Chronic sinusitis is a disease that afflicts a significant percentage of the population and causes considerable long-term morbidity. The common use of multiple broad-spectrum oral antibiotics and endoscopic sinus surgery to treat this condition may alter the pathogenes that promote persistence of chronic sinusitis. Forty-eight culture-positive patients with chronic sinusitis who had been medically treated for at least 3 months and had undergone sinus surgery were bacteriologically evaluated. Swab specimens of the middle meatus and sphenoethmoid recess were aseptically obtained endoscopically and cultured for aerobes. Coagulase-negative staphylococci were the most common isolates (45.8%), followed by Streptococcus pneumoniae (16.7%), Enterobacteriaceae (16.7%), Staphylococcus aureus (10.4%), and Pseudomonas aeruginosa (10.4%). Coagulase-negative staphylococci were the most frequently isolated organisms in our study, as in many other studies. Despite the significant predominance of these organisms, they have always been assumed to be contaminants, and their presence in culture has been discounted. Coagulase-negative S aureus may be a pathogen in the chronic sinusitis process, and sensitivities of this isolate should be obtained for evaluation and possible treatment of the disease.