A study on the microstructure and mechanical properties of two stainless steels, STS 304 and STS 430J1L, was performed in order to investigate their sticking mechanism during hot rolling. A simulation test was carried out using a high-temperature wear tester capable of controlling rolling speed, load and temperature. The results of the mechanical tests, together with high-temperature hardness tests, explained why sticking of the STS 430J1L took place more severely upon hot rolling, although the two steels had similar room-temperature hardness. The microstructural analyses revealed that the sticking process proceeded with three stages, viz, nucleation, growth, and saturation, for the both stainless steels. The coarse Cr carbides in the roll were also found to play no particular role on sticking.