A portable tissue equivalent calorimeter has been constructed and employed to measure absorbed dose in a mixed fast-neutron and gamma-ray field. Design details and measurement techniques are described along with the limits of precision and absolute accuracy. Experiments have been carried out with a cyclotron produced neutron beam using the 9Be(d,n)10B reaction at dose rates ranging from 3 to 25 rad/min. A series of ten measurements at a dose rate of approximately 10 rad/min were performed with a precision of +/- 2% (standard deviation about the mean). The compact design of this calorimetric dosimeter system facilitates transport to other laboratories for the measurement of absorbed dose in several complex radiation fields.