The Canadian Air and Precipitation Monitoring Network (CAPMoN) is funded and operated by Environment and Climate Change Canada (ECCC). It is an air-quality monitoring network consisting of twenty-eight sampling stations (one in the U.S.) at rural and remote locations. Its measurements support the Canada-U.S. Agreement on Air Quality, the Canadian Ambient Air Quality Standards for sulphur dioxide, ozone and fine particulate matter, and the Canada-Wide Acid Rain Strategy for Post-2000. CAPMoN monitoring of the major ions in precipitation follows the guidelines of the World Meteorological Organization’s (WMO) Global Atmosphere Watch (GAW) Precipitation Chemistry Programme and have been included in global assessments and model intercomparison studies. Since 1993, data from continuous monitors and post-laboratory analysis results have been quality controlled by an in-house developed software package called the Research Data Management and Quality Control (RDMQ) System. This software is based on the Statistical Analysis System (SAS ©). The RDMQ System loads data, applies customized quality-control checks and assigns data quality and validity flags. The system includes an interface to view, plot, and assign manual flags to data. After 27 years in operation, CAPMoN is modernizing the software and approach used to quality control the data. This poster describes the approach, expected benefits, and output of the new design.