A laboratory investigation was conducted to determine the potential utility of a commercially available passive dosimeter for monitoring toxic volatile organic compounds at ambient levels. Test compounds included: chloroform, methylchloroform, carbon tetrachloride, trichloroethylene, tetrachloroethylene, benzene, and chlorobenzene. The cause of the observed effect of air velocity on sampling rates was examined on a theoretical basis, and it is recommended that these devices not be employed without adequate ventilation. It is concluded that at least one currently available passive dosimeter could be useful for monitoring of ambient levels of toxic organic chemicals, and appropriate precautions are indicated.