An integrated heat sink with vapor chamber (IHSVC) is developed in this study for the thermal management of high-power light-emitting diodes (LEDs). The wick, as a key component of the IHSVC, is featured with parallel and orthogonal microgrooves, which were made using the micromilling method. Systematic experiments are conducted to characterize the thermal and optical performances, and the IHSVC is compared with the conventional heat sink (CHS) under the same operating conditions. Temperature rising tests indicate that the junction temperatures of the IHSVC system are always lower than those of the CHS at any current. In addition, the total thermal resistance R-j.a (from the junction to the ambient) of the IHSVC system is 0.83 degrees C/W, which is 16.5% lower than that of the CHS at 3200 mA (approximately 130 W). The temperature distribution of the IHSVC is also more uniform. As for the optical performance, the luminous fluxes and luminous efficacy of the IHSVC system are higher than those of the CHS device. Furthermore, it is found that the junction temperature has a negative effect on radiant efficiency. The radiant efficiency of the IHSVC system always outperforms its counterpart under the same junction temperature. The experimental results show that the high-power LED yields a favorable performance using the IHSVC unit.