The article contains the research results on the allelopathic susceptibility of oilseed radish to the main weed species that are dominant in its agrocenoses. The analysis of this indicator involved the research of the allometric reaction of oil radish on the treatment by aqueous extracts of 20 weed species in the concentration range from 1.0 to 4.0% in the period before the formation of true leaves. The morphological reaction to the applied extracts was determined using a number of index indicators assessing the ratio of growth and development of root and aboveground plant systems, the level of morphological depression of plants by linear characteristics, allelopathic potential etc. As a result of research, a dynamic range of harmfulness of the main weed species in terms of allelopathic potential in the range of 0.31-0.57 in relation to oilseed radish plants was established and the possibility of its use for biological control of weeds in the system of modern biologized agrotechnologies was determined.