The Problem Behavior Recording System (PBRS) is a computer-based monitoring system for tracking aggression and other problem behaviors among inpatients on neuropsychiatric units. The authors describe the system and compare it with other tracking systems. In 1997 a total of 405 aggressive incidents on an aggressive-ambulatory neuropsychiatry unit were recorded on the PBRS, whereas only 112 incidents, or 28 percent, were documented in hospital incident reports. In a further analysis, nursing notes in the charts of three patients were examined for a three-month period; 34 aggressive incidents were documented, compared with 41 PBRS entries for the same patients. The chart review took nearly three hours to complete, compared with less than five minutes for the PBRS analysis.