Functional endoscopic sinus surgery (FESS) has recently become a popular procedure for treating chronic sinusitis. However, there is a 2% to 24% rate of primary FESS failure. Revision functional endoscopic sinus surgery (RESS) is indicated for patients who remain symptomatic after primary FESS and optimal medical therapy have failed. A retrospective study was conducted on all patients who underwent RESS in our department between April 1988 and March 1998. During this period, FESS was performed 1,227 times to treat chronic sinusitis; among those procedures, 142 were RESS. Complications occurred in 14 RESS procedures (9.9%). After RESS, 65% patients had improved. In this study, we concluded that although RESS is more difficult than primary FESS because of distorted or missing anatomic landmarks, complications did not increase with RESS if meticulous surgical procedures were performed. However, the 65% improvement rate with RESS was lower than that of primary FESS.