Pesticides are essential in agricultural practices but due to their biocidal activity and potential risk to consumer, the control of pesticide residues in foods is The major source of concern for the population. This paper is conducted to evaluate tetradifon, deltametrin, and pymetrozin pesticide residues on cucumbers. For this purpose cucumber samples from 6 sites were collected after application of pesticides emulusions in autumn 1380 and summer 1381. In lab, the cucumber samples were analysed for the 3 pesticides by gas chromatography. The results showed that concentrations of pymetrozin and tetradifon pesticides in the collected cucumber samples of some sites were above the MRLs (maximum residue level). The results of Duncan s multiple range comparsions showed that, pymethrozin residue had significant differences (0.05) in Absard and Damavand road sites in summer and autumn.Advantages of the application of pesticides in agriculture in producing better crops must be weighed against the possible health hazard arising from the toxic pesticide residues in food.