Abstract: In this work we present both experimental and theoretical thermal analysis of an electrically pumped hybrid silicon evanescent laser. Measurements of an 850 m long Fabry-Perot structure show an overall characteristic temperature of 51 oC, an above threshold characteristic temperature of 100 oC, and a thermal impedance of 41.8 oC/W. Finite element analysis of the laser structure predicts a thermal impedance of 43.5 oC/W, which is within 5% of the experimental results. Using the overall characteristic temperature, above threshold characteristic temperature, and the measured thermal impedance, the continuous wave output power vs. current from the laser is simulated and is in good agreement with experiment.