The phylogeny of Formica ants in Korea was carried out using RAPD. Analyzing RAPD marker, the similarity degrees between species were estimated, and they were compared with the results from the measuring values of thirteen morphological characters. Morphological analysis showed as follows: all the five species were grouped with 72% or more similarity. Out-group, Camponotus was independently isolated. F. lemani and F. candida, F. yessensis and F. japonica were grouped in a very tight cluster with 97% or more similarity, while F. sanguinea+F. yessensis and F. japonica were grouped with 88%. On the other hand, RAPD analysis showed as followes: F. sanguinea, F. yessensis were grouped at the level of 97% similarity, F. lemani and, F. candida were also grouped with 97%. Both two groups were again grouped with 85% or more. This group and F. japonica were grouped with 72% similarity. In RAPD the lowest similarity was 72% in the five species of Formica. The positional homology of amplified fragments was identified by Southern hybridiztion of RAPD fragments. As a result, F. sanguinea and F. yessensis showed 97 % degree of similarity, and also F. lemani and F. candida showed 97%. F. japonica and above four species showed 72%. The level of similarity of F. japonica against the other four species was lower than those of four other species.