Recently, considerable improvements regarding the electrochemical performance of cathodes for lithium-ion batteries have been achieved by combining multiple lithium insertion compounds with complementary advantageous properties in one electrode. Herein, reversible heat generation rates of blended insertion electrodes are systematically investigated by temperature-dependent measurements of the equilibrium potential. The results are compared to theoretical predictions showing excellent agreement. Both the reversible heat profile and the corresponding dissipated heat significantly depend on the type and mass ratio of the constituents of the blend. The results indicate that reversible heat profiles of blended electrodes can be tailored to a certain extent by the targeted compilation of the active material mixture.