Carbon disulfide (CS₂) was determined at trace levels by its induction effect on the reaction of triiodide with azide in acidic media. The reaction was monitored spectrophotometrically by the decreased absorbance of triiodide over a period of 30 - 180 s from the initiation of the reaction at 350 nm, with calibration linear range of 0.020 - 1.870 μg/ml CS₂. The limit of detection is 0.013 μg/ml CS₂. A carbon-active column was used for sample solution clean up. The proposed method was successfully applied to the determination of trace carbon disulfide in natural water.