Aim: Improper colonoscopy requests from different medical fields, especially like in an open access endoscopy unit, increases workload of the unit and healthcare expenses. For standardize these requests, eligibility criterias emerged. The aim of this study was to evaluate the appropriateness of colonoscopy requests performed in an open-access endoscopy unit of a university hospital and determine possible causes of the improper requests by patient characteristics, colonoscopy indications and results.Material and Methods: Between January 2009 and January 2015, 3259 patients who were referred for colonoscopy in an open-access endoscopy unit of a university hospital were enrolled into study. Post-procedure colonoscopy reports, along with their diagnoses, were recorded. All records were then evaluated retrospectively and the patient’s indications and patients’ results were compared and reasons for improper requests were discussed.Results: The mean age of the patients who underwent colonoscopy was 56.68 year, and 56.2% of the patients were males. When the requests were placed in order of frequency, the first three cases were rectal bleeding, anemia, and abdominal pain. Most of the patients did not have any pathology on colonoscopy (37.8%, n = 1238). The other most common diagnoses were hemorrhoids and colon polyps. Malignancy detection rate by colonoscopy was 5.3%. Associations between requests and results were detailed.Conclusion: Eligibility criterias should be used to minimize inappropriate requests and training should be provided for experts about colonoscopy these criterias, or a gastroenterologist should be consulted before colonoscopy procedure, especially for open-access endoscopy units