Three strains of W isolated from tobacco, tomato and Pepper plants in Korea were characterized based on biological response, serological relationship, and peptide mapping of the capsid Proteins. The strains designated as TMV-common, TMV-Pepper, and TMV-tomato could be distinguishable by different visual symptoms on 3 varieties of tobacco, one variety of tomato and Pepper for each among 27 plant specieces. Serological relationships were examined by agar gel double diffusion test. Only traceable or weak reaction was observed in the incompatible antigen-antibody combinations. The Pepper strain, however, showed trace in reaction with other two antisera. Peptide maps of the capsid proteins digested by V8 protease or by trypsin were also distinguishable, suggesting differences in composition and/or sequence of the amino acids among the strains. Key words : TMV, strains, tomato, pepper, tobacco