Schools are now required by law to create behavior support plans based on functional behavioral assessment (FBA) for students with behavior problems. Although FBA has been shown to be effective, there are questions as to its feasibility in the schools. In this pilot study we examined the effectiveness of a truncated FBA procedure. The FBA used a simplified procedure for the teacher to identify the function of a behavior and to formulate a hypothesis. Results suggested that the teacher was able to select the probable function of the problem behavior, formulate a summary statement and design an intervention with guidance from the researcher. Problem behavior decreased during intervention and maintenance. Teacher acceptance of the truncated FBA procedure was confirmed with a social validity questionnaire.