This Test Guideline describes procedures designed to assess bioaccumulation of chemicals in soil oligochaetes. The parameters which characterise the bioaccumulation of a substance include the bioaccumulation factor (BAF), the uptake rate constant (ks) and the elimination rate constant (ke). The test consists of two phases: the uptake (exposure) phase and the elimination (post-exposure) phase. An elimination phase is always required unless uptake of the test substance during the exposure phase has been insignificant. The test organisms are exposed to the test substance during the uptake phase. The test substance is incorporated into the soil; it is recommended to use the artificial soil described in the OECD Test Guideline 207 (Earthworm, acute toxicity test). The uptake phase should be of 14 days (enchytraeids) or 21 days (earthworms) unless it is demonstrated that steady state has been reached. For the elimination phase, the worms are transferred to a soil free of test substance. The elimination phase is generally of 21 days.