The aim of the study: to evaluate the effect of nursing educational methods on the quality of bowel cleanliness for patients undergoing colonoscopy. Research design: Quazi-experimental research design was be utilized. Subjects and methods: a purposive sample of 60 adult patients divided into two groups (control and study) 30 patients for each. A study conducted in Internal medicine, General surgery departments and Gastrointestinal Endoscopy Center at Assiut University Hospitals. Tools: Only one tool was being utilized; patient assessment sheet. Results: more than half of patients (53.3%) in control group have bad level of bowel cleanliness with mean score of Boston bowel preparation scale (BBPS) was (2.7 + 2.4), while more than half of patients in study  group  (56.7%) have excellent level with mean score of (BBPS) was ( 6.7 + 1.2). Conclusion: educating colonoscopy patient using nursing educational methods as video and booklet are considered a cornerstone in achieving accepted level of bowel cleanliness. Recommendation: Sufficient relevant written and visual information to facilitate educating   patients about proper preparation of the bowel before colonoscopy and educating patients about  signs and symptoms of the potential complications after colonoscopy for seeking rapid medical advice