ABSTRACT Background: Fifty-five percent of Americans aged 50-65 are submitted to colonoscopy. For over 65-year, this number increases to 64%. In Brazil, it is forecast that the population submitted to colonoscopy will grow, even though inadequate preparation is still a major problem. Aim: To analyze the quality of a new intestinal preparation technique, Aquanet EC-2000®, compared to oral Mannitol solution. Methods: This prospective longitudinal study enrolled 200 patients with indication for colonoscopy. The sample was randomly allocated to two groups of 100; one group received Aquanet EC-2000® to prepare for colonoscopy and the other Mannitol solution. The Boston scale was used to analyze the results. Results: As expected both preparations produced similar results with the bowel cleansing of the different regions of the colon being classified as Boston scale 3 (excellent) in most patients (p>0.05). Conclusion: The results of bowel preparation using Aquanet EC-2000® were similar to using Mannitol solution.