Data on the observed concentrations of three hundred twenty (320) volatile organic compounds (VOCs) were compiled, critically evaluated, and assembled into a relational data base. Ambient (i.e., outdoor) measurements, indoor data, and data collected with personal monitors are included. The data are primarily from the period 1970-1987 and for locations within the United States. In order to compare data from many different sources, each concentration record in the data base represents the daily average for a single chemical, wherever feasible. The total data base contains more than 175,000 concentration records. Summaries of the data distributions are tabulated in the report. Averages, medians and quartile values are given for each chemical measured in both the ambient and indoor site categories. Median values are also listed for each chemical for the eight specific site types included in the data report. The ambient site types are: remote, rural, suburban, urban, and source dominated. The indoor category of site types include residential indoor, workplace (non-industrial), and personal monitors. The data have been assembled into a relational data base using dBASE III Plus, a commercially available data base management program. The report contains a complete description of the data base files and a guide describing the use of a prepared program for searching and maintaining the data base.