Mucosal biopsies, endoscopically-guided brush samples of mucus, and a saline lavage taken from the maxillary sinuses of ten CRS patients undergoing sinus surgery are analyzed using three microarrays: 16S rRNA PhyloChip (to detect bacteria), MycoChip (to detect fungi) and ViroChip (to detect viruses). Ten control patients with normal sinuses, as assessed by CT scan and a sinusitis-specific survey, will have the same samples taken. The hypothesis is that bacterial, fungal, and viral communities present in the maxillary sinus of patients with CRS are significantly different from those patients with healthy sinuses, and that microorganisms identified in patients with or without CRS will differ from previously published data obtained using other techniques. Comparing diseased and control flora will provide insight into the relative contribution of each pathogen to CRS and may guide the development of future therapies.