A simple, fast chemiluminescence (CL) flow-injection method based on the reaction of luminol with H2O2 in the presence of a cationic surfactant (cyltrimethylammonium bromide, CTMAB) has been described for the direct determination of dichlorvos pesticide (DDVP). Under the optimal conditions, the CL intensity was linear to the DDVP concentration in the range of 0.02–3.1 μg ml−1 (r=0.9998, n=10). The relative standard deviation was 3.4% at 0.35 μg ml−1 (n=10), with a detection limit (3σ) of 0.008 μg ml−1 DDVP. The possible reaction mechanism was also discussed. This method has been successfully applied to the determination of trace DDVP residue in vegetable sample and results have been compared with that of the UV method.