Objective: To compare the effects of the simplified 5-step and the conventional 7-Step hand hygiene programme in a cluster randomized controlled trial among students with intellectual disabilities. Method: A total of 472 Chinese students with intellectual disabilities were randomized to either simplified 5-step or conventional 7-step hand hygiene programme. Assessments included handwashing technique, cleanliness and sick leave days. Results: Handwashing technique scores (g = 0.25, 95% CI [0.18, 0.32]) and hand cleanliness scores (g = 0.33, 95% CI [0.26, 0.4]) in intervention group were significantly higher than those scores in control group at 6th month post-intervention although there were significant increases in the scores within both groups. The mean number of sick leave days decreased between baseline and 10 month in both groups according to descriptive statistics. Conclusions: It is feasible and effective to adopt the simplified 5-step intervention as a standardized handwashing technique for the population group with intellectual disabilities.