There are a variety of measurement techniques available to determine the thermal conductivity and thermal impedance of a material. The two main categories of techniques used to measure thermal conductivity include steady-state and transient. Both types provide a temperature gradient through a known power input, and the response of the material to the gradient is monitored. The procedures vary in areas including sample size, testing time, and range. To determine the proper measurement technique for an application, the decision should be based upon three factors. First, knowledge of the sample including geometry, size, and material preparation. Second, the fundamentals and procedures for the testing technique. Finally, the potential error sources which may affect the final results. The engineer will review each method in greater detail to better understand the advantages, disadvantages, and sources of error for each.