People with intellectual disabilities have difficulty making decisions and this may hinder their independence and inclusion in society. Interactive computer software may give them the opportunity to practice the underlying components of this skill. A previous study indicated that playing a computer game improved choice reaction time. This study aimed to discover if repeated sessions playing a computer game involving aspects of decision making, such as collecting relevant information and controlling impulsivity, would improve performance in two non-computer based tests of decision making. 12 adults with intellectual disabilities were randomly assigned to either an intervention group or control group. They were all exposed to 10 twice weekly sessions, playing either the intervention game or the control game, which involved simple reaction time only. All participants completed two non-computer based tests of decision making at baseline and post-intervention. After repeated sessions, the intervention group showed a significant improvement in game score, with researcher assistance significantly decreasing. At follow up, the intervention group showed a significant decrease from baseline in the number of guesses made before guessing correctly on both of the decision making tests. The decrease observed in the control group failed to reach significance.