Various kinds of lasers have been developed and applied to a variety of lesions in medical and dental fields. However, few papers have reported in detail how to use contact lasers in oral and maxillofacial surgery. Here we describe how to use Nd: YAG and KTP contact lasers in surgery for head and neck tumors, and specify the advantages and disadvantages of scalpels, electric knives, and contact lasers.The 169 subjects had head and neck tumors (28 benign, 141 malignant) treated with Nd: YAG or/and KTP contact lasers during the period 1998-2002. A KTP/YAG laser (Model SL 20/50, Laserscope) was most commonly used, although an SLT contact laser (DCL-50, SLT Japan) and an Nd: YAG laser Hercules 5100 (Laser Sonics) were also used occasionally.The above lasers were mainly used for hemostatic cutting. In the KTP/YAG system, the Nd: YAG laser was basically applied at 12-13 W with quarz fiber (0.6mm diameter) held using a microstat handpiece. Power was increased to 17-18 W, when cutting was difficult. For larger tumors, the KTP laser was used at more than 10 W. Both lasers were used in continuous mode. In all cases, cutting was performed satisfactorily with the Nd: YAG or/and KTP contact lasers according to the above conditions.Based on our experience, we specified the advantages and disadvantages of scalpels, electric knives, and contact lasers, as follows. Scalpels cut the fastest, but offered no hemostasis. Electric knives (cutting mode) were second in cutting speed, but less effective in hemostasis than lasers. Where hemostasis was important, electric knives were used in coagulation mode. However, the cutting speed decreased in this mode. The KTP contact laser was slower to cut than electric knives, but more effective than the latter in hemostasis. The Nd: YAG laser was slowest in cutting among the four instruments. However, this laser was next to the KTP laser in hemostatic cutting. In addition, the glass filter for the Nd: YAG laser was not as dark as that for the KTP laser, which latter caused surgeons to have difficulty discerning anatomical structures during surgery. As a result, we used the Nd: YAG laser primarily, and the KTP laser for larger tumors requiring more hemostatic cutting.The present study demonstrated the advantages of Nd: YAG and KTP contact lasers used appropriately in oral and maxillofacial surgery.