A computerized system has been developed to assist in U.S. Environmental Protection Agency data validation studies of organic analytical data collected for hazardous waste site assessments. The Regional Automated Data Auditing System (RADAS) is a data evaluation and management computer program that provides data entry, file maintenance, data qualifying, and report generation for results from gas chromatography and gas chromatography/mass spectrometry analyses. The RADAS system determines the validity of individual analyte concentrations reported by the laboratory. This determination is based on instrument calibration, sample holding time, blank contamination, and contract required detection limit. Delivery-ready reports are produced, including data tables, sample and calibration listings, and a documented summary of data validation. The system developed has been found to perform appropriately and its use represents a significant improvement in terms of turn-around time, completeness, and consistency of data validation studies.