This study investigates the residues resulting from the treatment of soybean plants with 1‐14C‐2,3,5‐triiodobenzoic acid. TLC was used to characterize and quantitate the residues present in the various samples. Residues of 1‐14C‐2,3,5‐triiodobenzoic acid, 1‐14C‐2, 5‐diiodobenzoic acid, and 1‐14C‐3,5‐diiodobenzoic acid were found in the various plant parts and in the harvested seeds. The seeds also contained a large amount of the 14C activity as a hexane‐soluble material which was not identified. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company