Tetranychid mites are one of the most diverse group including at least 1,200 species in the world. Species identification is difficult due to the small size and similar morphology within the group. We collected 17 species of spider mites from various host plants in different regions of Korea and determined species identity by the comparison of morphological characters and nucleotide sequences of internal transcribed spacer 2 (ITS2) and the cytochrome oxidase subunit I (COI). In addition, we report three new species that were firstly identified in Korea. Amphitetranychus quercivorus (Ehara and Gotoh) was collected from Mongolian oak plant in Daegu, Schizotetranychus miscanthi Saito was from the common reed plant in Ulleungdo, and S. cercidiphylli Ehara was from Bamboo plant in Jeju. Morphological identification of three species were similar with those of Japanese samples, but the ITS2 and COI sequences of A. quercivorus and the COI sequence of S. miscanthi were different with Japanese species at the rates of 1/419, 2/331 and 3/332 nucleotides, repsectively. S. cercidiphylli can be identified by the aedeagus shape of males but we firstly sequenced ITS2 and COI of this species. Our results can be used for the identification of spider mites which are important in plant quarantine.