In vivo flooding was used to treat an intense fear of balloons (noise) in a college-aged man. Behavioral and self-report measures of fear and avoidance indicated that (a) the subject avoided all situations in which he might encounter balloons, (b) he reported that the fear caused him considerable distress, and (c) he could approach no closer than 4 feet from a balloon with intense fear during a behavioral avoidance test prior to treatment. Three sessions of flooding conducted on 3 consecutive days involved exposure to and participation in the popping of hundreds of balloons. Following the three flooding sessions, the subject showed no avoidance behavior and reported almost no subjective distress in the presence of balloons. Furthermore, the subject stopped avoiding situations in which he might encounter balloons and reported no further distress in his life related to balloons.