Karen, the subject of this case study, was a 10-year-old girl diagnosed as having attention deficit hyperactivity disorder and provisionally obsessive compulsive disorder. She was adopted by her present parents when she was 8 years old, after having been in foster care. Evidence of Karen's stealing involved directly observing her take an object without permission, finding a student's or adult's possessions on her person or in her desk, and having a student or adult report that she had taken something from him/her. Occurrences were recorded as a "stealing incident" by the primary teacher on a precoded data sheet. Baseline data were recorded for 7 weeks under conditions that were operative preceding the study. A functional assessment suggested that the stealing behavior was maintained by the social attention it elicited from school personnel and parents. Using an hypothesis-driven model of treatment formulation, intervention consisted of eliminating multiple sources of attention in an extinction paradigm. Intervention was associated with a systematic reduction in stealing, and results were maintained through a 12-month follow-up. Issues related to functionally determined treatment of behavior disorders are discussed. 1 figure and 11 references