This study applied the structured observation technique developed by Mintzberg to the high school principalship. Observation of the activities performed by five principals resulted in a characterization of school administration that paralleled private sector management in many respects. Principals exercised building-level authority over such matters as organi zational maintainance, the administration of the instructional program, pupil control, and extra-curricular activities. They spent comparatively little time on affairs external to the school organization. Although their work pace was hectic, there were certain cyclic features which could be identified.