Pesticides improve crop yields, but misuse imposes environmental problems and diseases or abnormalities in humans. Based on food security definition, balanced attention to healthy and sufficient products, there is a growing need to pay attention to product health. The present study was aimed to measure the residual levels of chlorpyrifos (CPF) and diazinon (DZN) in potato Solanum tuberosum L. cv. Agria and their chips by accurate, rapid, and reliable extraction method (QuEChERS) using gas chromatography equipped with NPD detector (GC-NPD). The samples were analyzed in pre-harvest stages, harvest, and storage. The recovery of DZN was 95.76–99.87% and 82.38–98.05%, and the CPF 90.85–99.07% and 79.4–89.76% in potatoes and chips, respectively. According to the specifications of the European Commission, the relative standard deviation (RSD) of <11% detected in this study confirms the accuracy of the extraction method. Moreover, the CPF residual level was detected only in the pre-harvest stage; however, the DZN residual levels in the pre-harvest, harvest, and storage stages, and chips were 0.074 ± 0.007, 0.039 ± 0.014, 0.029 ± 0.009, and 0.13 ± 0.042 μg.g^-1, respectively. The residual level in chips and harvest and storage stages was higher than that in the maximum residue level (MRL).