Antibodies against the herbicide chlorsulfuron have been raised and characterized. Enzyme immunoassays (EIAs) for chlorsulfuron, involving labeled antigen or labeled antibodies, have been developed. The kinetics of antigen-antibody interactions in the EIA systems developed has been studied. Both systems exhibit equal sensitivity (1 ng/ml). The values of the coefficient of variation (CV), determined within the range of chlorsulfuron concentrations 1-100 ng/ml to be measured by the systems, are not in excess of 8%. The possibility of using glucose oxidase as a label in EIAs for chlorsulfuron has been demonstrated. Lack of cross-reactivity with a series of sulfonyl- and arylurea derivatives and triazines makes it possible to recommend the EIA systems developed for chlorsulfuron determination in the environment.