The thermal stress distribution of WC and Ni binder phases In WC-26st.%Ni and WC-6wt.%Ni composites has been investigated over the temperature range 100-900 K using a time-of-flight neutron diffractometer. To determine the stress distribution, the breadths of WC and Ni peaks in the reference powder and the composites were analyzed. The peak breadths were corrected for particle size effect using a procedure based on the integral peak breadth method of particle size-strain analysis. The result shows a broad range of strain, and thus stress, is present in the WC and Ni binder phases of the composites. The strain distribution of both phases broadens as the temperature decreases, and some fraction of total strain distribution of the WC phase remains tensile regardless of the temperature. The strain distribution of the WC phase broadens as the binder content increases, and that of Ni binder phase broadens as the binder content decreases, which means the strain distribution broadens as the absolute value of residual stress increase.