SUMMARY Colonoscopy has a broad range of indications including evaluating lower gastrointestinal disorders. Also therapeutic applications of colonoscopy nowadays carry promising technical improvements. Colonoscopy has revolutionized the clinical management of colonic diseases. Colonoscopy represents a cost effective means for detection of colorectal lesions due to its relatively low incremental costs. Aim of the work: The aim of the present study is to evaluate the value of colonoscopy in diagnosis and management of lower gastrointestinal disorders in Upper Egypt. Patients and Methods: One hundred patients underwent lower gastrointestinal endoscopy, 62 males and 38 females with a mean age (36.6y.) All selected patients were complaining of lower gastrointestinal disorders in the previous six months. Patients were subjected to thorough history taking & full clinical examination, stool analysis, test for occult blood in stool, complete blood picture, erythrocyte sedimentation rate, chest x ray, abdominal ultrasonography, total colonoscopy with colonic biopsy when indicated & histopathological examination of the biopsy with H & E staining. Conclusions: Inflammatory and/or ulcerative colorectal lesions are the most common colonic lesions as they were detected in (30%) of patients; of which non specific colitis (40%), ulcerative colitis (26.7%), bilharzial colitis (20%), Crohn's disease (6.7%), amoebic colitis (3.3%) and one case was diagnosed as adenocarcinoma grade III (3.3%). The relative decreased number of schistosomal colitis and amoebic colitis can be attributed to the effectiveness and the widespread use of anti-schistosomal and anti amoebic drugs respectively. Colorectal polyps are the second commonest colorectal lesions (16%). Adenomatous polyps represent 37.5% of cases of colorectal polyps in our study. Colorectal carcinoma is a common malignant neoplasm in Egypt; it represented (8%) of all cases in our study. The high proportion of patients with normal colonic mucosa in spite of different colonic manifestations; may be attributed to functional bowel disorders especially irritable bowel syndrome. Colonic diverticulosis is not rare in our country probably due to the western cultural influence in our diet and lifestyle.