Objective: To compare the efficacy of bowel preparation with an olive oil plus low volume (2 liters) polyethylene glycol-electrolyte lavage solution (PEG-ELS) and conventional volume (4 liters) PEG-ELS solution. Study Design: Randomized, Controlled Trial. Setting: Lahore General Hospital. Period: September 2017 and November 2018. Material & Methods: Patients were randomly assigned to two groups. Group A patients were given olive oil plus low volume (2 liters) PEG-ELS and Group B patients were given conventional volume (4 liters) PEG-ELS solution. Achievement of the adequate preparation was assessed using the Boston Bowel Preparation Scale (BBPS). A questionnaire was used in assessing the ease or difficulty of ingesting the bowel-cleansing preparation. All analysis was conducted with SPSS 20.0. Results: Of the total 162 patients randomized, 24 were excluded due to various reasons. Of 138 studied patients, mean age was 40.88 ± 13.75 years, 90 (65.21%) were male and 48 (34.78%) were female. Overall, 42 (30.4%) patients had Boston Bowel Preparation Score (BBPS) 8 and 9 indicating excellent bowel preparation, 38 (27.5%) had good bowel preparation with score 6 and 7, 30 (21.7%) patients had poor bowel preparation with score 3-5, and 28 (20.3%) patients had inadequate bowel preparation with score 0-2. The mean BBPS was 6.11 ± 2.6 with the olive oil preparation and 4.63 ± 2.81 with conventional PEG-ELS preparation (P = <0.005). More patients in Olive Oil group had excellent bowel preparation as compared to conventional group (43% versus 15%, p <0.005). The mean time of examination was 23.2 minutes in Group A and 21.85 in Group B (P <0.05). Mean time for colonoscopy was much higher (28.75 min.) in patients with a BBPS score of < 3. 61%of patients in Olive Oil group experienced no side effects as compared to 43% in the conventional PEG-ELS group (p < 0.05). Abdominal pain was the most common side effect observed, more frequent in the conventional PEG-ELS group (30% versus 4.9%, p<0.05). Conclusion: Low volume PEG plus olive oil is a valid alternative and more applicable to bowel preparation for colonoscopy than conventional volume PEG, with superior efficacy, better compliance and tolerability and better safety profile.