The purpose of this work was to establish the stability of volatile organic compounds in environmental water samples. The stability of common volatile organic compounds was determined in three types of waters, distilled water, a groundwater, and a surface water. Two concentration levels were studied: nominally 50 micron/L and 500 micron/L. Samples were stored at two conditions, room temperature and under refrigeration (4C). Samples were analyzed at intervals of 0, 3, 7, 14, 28, 56, 112, and 365 days. The data from this study indicates that most volatile organic compounds are stable in water for longer than 365 days. Exceptions to this statement include compounds prone to dehydrohalogenation (e.g. 1,1,2,2-tetrachloroethane) and compounds prone to biological degradation, particularly the volatile aromatics. The stability of the compounds was matrix dependent and storage condition dependent. Within the limits of this study, the minimum holding time for an environmental water sample prior to analysis for volatile organic compounds is about ten days, although for most of the compounds, stability is not a problem up to 365 days.