The line heat source probe method, widely used for determining thermal conductivity of food materials, was applied in a pilot scale high-pressure unit and the possibility of extending this technique to pressures up to 400 MPa was investigated. Commercially canned tomato paste and apple pulp were used as test products. Probes were calibrated to 1.5% agar gel. A probe specific pressure- and temperature-dependant calibration factor was applied. The accuracy at high-pressure was similar to published values. Given the simplicity of the method, this approach seems very promising for determining thermal conductivity of foods over a range of pressures and temperatures.