Walking behavior was established in a 20-month-old Down's Syndrome girl by a parent trained in behavior analysis. During a series of 7-minute sessions, the child was given edible reinforcement for taking unsupported steps between two chairs which were gradually moved from 18 to 70 inches apart. In three final generalization sessions, the chairs were removed and the child was reinforced for walking unsupported from one parent to the other. Walking was firmly established with a total expenditure of 3 hours, 9 minutes time. Benefits of the procedure included the involvement of a minimum of time and preparation and the use of family members as teachers. (LS)