Background: Persons with intellectual disabilities (ID) constitute a special-needs population at high risk of falling. This is the first study to evaluate whether obstacle course training can improve mobility and prevent falls in this population. Methods: The intervention was implemented as part of an institution-wide health care improvement plan aimed at reducing falls at a residential facility for people with ID. It comprised an annual screening of each resident for his or her individual fall risk. Subsequently, the group of ambulatory persons with a moderate to high fall risk ("n"?=?39) were offered 10-session obstacle course training to improve their balance and gait abilities. Mobility was assessed pre-intervention, mid-term and post-intervention with the Performance Oriented Mobility Assessment (POMA), the Timed Up and Go (TUG) and the 10-meter walking test. The number of falls was compared between the year before and after intervention. Results: The number of falls decreased by 82% ("P"?<?0.001). POMA scores significantly improved from pre-intervention to mid-term (mean difference?±?SD, 1.8?±?2.9, "P"?=?0.001), from mid-term to post-intervention (2.0?±?2.9, "P"?<?0.001), and from pre-intervention to post-intervention (3.8?±?4.3, "P"?<?0.001). Participants completed the 10-meter walking test faster at the post-intervention compared with the pre-intervention assessment (difference?±?SD, 2.1?±?5.1?s, "P"?=?0.022). TUG scores did not improve significantly. Conclusions: The present study provides preliminary evidence for the effectiveness of obstacle course training in improving mobility and preventing falls in people with ID. As falls are a significant health concern in this population, further research is advocated to provide conclusive evidence for the suggested beneficial effects of exercise interventions.