The serotyping of staphylocoagulase is widely used in Japan. However, the conventional immunoassay based on neutralization of the antisera is so laborious and time-consuming that it is not widely used in the other countries. In order to overcome these drawbacks we developed a novel staphylocoagulase serotyping method based on a microplate format using polystyrene latex particles. Addition of latex particles promotes the formation of fibrin complexes, which represents a more rapidly and easily detected endpoint. For 83 strains, 90% were classified into serotypes within 3 h, and there was no discrepancy in the results between our method and the conventional method. These results indicate that the present microplate method is rapid, simple, and interpretable.