Clinical response of congenital melanocytic nevus (CMN) to the combined normal-mode ruby laser (NMRL) and Q-switched ruby laser (QSRL) treatment method (ie, NM plus QS) was correlated with the histologic depth of nevomelanocytic nests to predict the efficacy rate and therapeutic outcome of the laser treatment. Thirty-four patients with CMN were treated using the combined (NM plus QS) ruby laser method. The clinical results of the laser treatment demonstrated that 20 had excellent response, 11 had good response, 3 had fair response, and there was no poor response. When correlated with the histologic type, the efficacy rate of the combined ruby laser was significantly higher in the superficial intradermal type than in the others. We conclude that combining the NMRL and QSRL with appropriate parameters to target both superficial and deep nevomelanocytic components provides a greater degree of penetration of laser light.