A high-sensitivity dosimeter system was developed to measure low gamma-ray dose rates in the presence of neutrons. The detector is a liquid scintillator that employs hexafluorobenzene (C6F6) as a solvent and is practically hydrogen free. The energy absorbed in the scintillator is determined directly by counting the analog-to-digital converter pulses of a multichannel analyzer in a fast scaler. The ratio of energy absorbed to air exposure dose was measured for incident gamma energies of 0.06 MeV (241Am), 0.66 MeV (137Cs), 1.25 MeV(60Co), and 4.43 MeV (241AmBe) and gave an average deviation of 3.5% from a constant ratio of energy absorbed to air exposure. A Monte Carlo computer program was written to determine the response of the scintillator to a broader range of gamma-ray energies. This indicated that the ratio of the energy absorbed to the air exposure would vary within the limits of ±10% from 50keV to 10 MeV. The response to fast neutrons also was measured and compared with calculations which showed that the major component in the neutron response was produced by β− decay following the (n,α) reaction in 19F. For the broad spectrum of incident fast neutrons (up to 11.5 MeV) from a 241AmBe source, the neutron response of the dosimeter was found to be < 8% of its response to the comparable flux of 4.43 MeV gamma rays from the source.