4-Chloroaniline-14C was applied to soil in a lysimeter, corresponding to about 1.25 ppm to a depth of 10 cm, and barley was sown. After 20 weeks, a total of 32.8% of the radiocarbon applied was recovered, in soil 32.4%, in plants 0.3%, and in leaching water 0.1%. The radioactivity in soil consisted of 30.8% unextractable residues and 1.6% soluble conversion products; that in plants consisted of 0.24% unextractable residues and 0.03% soluble metabolites (percent of applied 14C). In the second and third year after the application, potatoes and carrots, respectively, were grown; total recoveries were 32.0% and 31.2%, respectively. The soluble radioactive fractions in soil and plants of the two first years contained 4-chloroformanilide (I), 4-chloroacetanilide (II), 4-chloronitrobenzene (III), 4-chloronitrosobenzene (IV), 4,4′-dichloroazoxybenzene (V), and 4,4′-dichloroazobenzene (VI). The radioactive substances unextractable in soil and those in leaching water were partially hydrolyzable and gave 4-chloroaniline.