The present paper outlines the establishment of four additional cloned cell lines derived from embryo tissues of Bombyx mori, which were designated as SES-BoMo-J125K1, SES-BoMo- J125K2, SES-BoMo-J125K5, and SES-BoMo-J125K6. These cell lines were characterized by their suspension-type, karyology, isozyme pattern, and amino acid consumption pattern. Among these cell lines, the SES-BoMo-J125K2 cell line was susceptible to Bombyx mori nuclear polyhedrosis virus, and could be cultured in the serum-free medium (MM-SF). This cell line could be used for the production of useful proteins or to control pests using baculoviruses.