Familial adenomatous polyposis (FAP) is a rare genetic disease. Without treatment, FAP patients have a 100% lifetime risk of developing colorectal cancer. This study was conducted to evaluate the effect of celecoxib treatment in prolonging the time to FAP-related events and to document the safety profile of the long-term use of celecoxib (=6months) in FAP patients. FAP patients receiving celecoxib in routine clinical practice were individually matched with historical/concurrent FAP patients not receiving celecoxib. The study population included patients aged 12years or older registered in national and regional FAP registries in Denmark, the United States, Spain, and Canada. Descriptive statistics were used to summarize dose and duration among celecoxib treated patients. The primary study endpoints, time-to-next-FAP events, were examined with Kaplan-Meier method. Fifty four celecoxib-treated patients were recruited and a matched control was identified for 13 of these patients. The Kaplan-Meier estimated probability of not having a polypectomy 12 and 60months post- ileorectal anastomosis in the celecoxib-treated patients (n=33) was 60.6% and 42.2%, respectively. The estimated probability of not having a polypectomy 6-60months post-ileal pouch-anal anastomosis the celecoxib-treated patients (n=24) was 100%. The median total daily dose of celecoxib was 698.9mg with the majority treated more than 24months. Five celecoxib-treated patients experienced 6 serious adverse events with one of these events (rash) considered related to celecoxib. Long term celecoxib treatment appeared to be well tolerated in FAP patients with or without FAP-related surgeries.