Colonoscopy is widely used as a tool for diagnosis, screening and treatment of various pathologies in the rectum, colon, and terminal ileum. The aim of this study is to evaluate the demographic, clinical, and histological parameters of the records of patients undergoing colonoscopy at a tertiary care hospital in Nepal. This retrospective cross-sectional study included the hospital records of all patients who underwent colonoscopy from 2015 to 2019 in a tertiary care centre in Nepal. A total of 1255 records were included in the study. The mean and standard deviation of age were 43.8 and 19 years, respectively. Among the total study population, 61.9% were males and 38.1% were females. Common indications for colonoscopy included lower gastrointestinal bleeding (27.7%), altered bowel habit (26.9%) and persistent or recurrent abdominal pain (17.3%). Only 3% of the patients who underwent colonoscopy had inadequate bowel preparation. The overall diagnostic yield of colonoscopy was 57.5%. Findings during colonoscopy included colorectal polyp (19.4%), internal haemorrhoids (8.2%) and colitis (6.5%). Having an age of 50 or more years was significantly associated with the presence of colorectal adenocarcinoma (P=0.017, χ2 test) with an odds ratio of 2.35 (95% CI: 1.14, 4.89). Furthermore, having a female sex was found to be significantly associated with the presence of colorectal adenocarcinoma (P=0.012, χ2 test) with an odds ratio of 2.43 (95% CI: 1.19, 4.97). In the authors' study, a smaller proportion of the colonoscopies was aimed at screening for colorectal carcinoma (CRC), when compared to studies in developed countries. The sex predisposition of CRC in the authors' study is in contrast to the global trend. The authors recommend conducting studies to determine the risk factors and need for CRC screening in the Nepalese population.