The variation of the low-temperature thermal resistance of single crystals of zinc in large magnetic fields has been investigated. The work was divided into two parts, one using very large fields (H<=60 kilogauss) and the other using fields ranging to 25 kilogauss. The high-field work was concerned mostly with the behavior of the thermal magnetoresistance for various orientations of the crystalline axes relative to the magetic field. It was found that the thermal magnetoresistance is a strong function of orientation in the field, and an attempt was made to extrapolate the data obtained to infinite fields. The low-field work was carried out primarily to investigate the de Haas-van Alphen effect, and electrical as well as thermal magnetoresistance data were taken. Oscillations of the de Haas-van Alphen type were found in both the thermal and the electrical magnetoresistance and an average value of β*E0=5.8×10-5 gauss-1 was derived from the thermal data. Comparison with theory yielded a value of the order of 0.2 electron per atom for both the thermal and electrical cases. The variation of the Lorenz ratio with magnetic field was also derived.