IR5885 degraded very fast: after 72 hours its amount was near 3% AR. The decline of IR5885 was represented by a first order kinetic. DT50 lab was 12.00 hours, while DT90lab was 39.87 hours. Four degradation compounds were found in soil extracts (S2, S3, S4, and S5). The main degradation compounds were: S2 and S3. The compound S2 reached a maximum value at 16 hours, then it decreased. Its decline was represented by a first order kinetic. DT50lab values was 16.54 hours, while DT90lab values was 54.96 hours. The compound S3 was formed more slowly than the compound S2; it increased till 48 hours, and then started to decrease. The compounds S2 and S3 were identified as IR5885-acid, and 4-chlorobenzoic acid by co-TLC analysis with the corresponding reference standards and by MS.HPLC analysis of soil extracts showed a degradation of S,R diastereoisomer faster than the S,S diastereoisomer of unchanged IR5885 (S1). Also the IR5885-acid S,R diastereoisomer degraded to S3 more quickly than S,S diastereoisomer. The non-extractable radioactivity (bound residue) increased during the incubation period, reaching the maximum values at the last sampling time. The fractionation of organic matter was carried out only at 72 and 96 hours, where the bound residue was higher than 20% AR. Volatile radioactivity, as 14C-CO2, progressively increased during the incubation period reaching a maximum value of 26.96% AR. The mass m balance was always higher than 92% AR.