The soluble protein pattern was analyzed using two-dimensional electrophoresis in bean normal and tumor callus. The normal callus was subcultured on the medium supplemented with 2.5 μM picloram and 5 μM kinetin and the tumor callus was subcultured on the medium supplemented with or without 2.5 μM picloram. There were some differences in soluble protein pattern between normal and tumor callus. In the tumor callus grown on the hormone-free medium, 2 proteins were induced, 7 proteins were suppressed, and 2 proteins were induced, 7 proteins were suppressed, and 2 proteins were enhanced in comparison with the normal callus. In the tumor callus grown on the 2.5 μM picloram containing medium, 3 normal specific proteins that disappeared in the picloram-untreated tumor callus disappeared also, 4 normal specific proteins reappeared and tumor-induced 2 proteins were reduced at the same level of the normal callus. These results indicate that picloram-treated tumor callus has the characteristics of both normal and tumor callus in protein pattern.