The aim of this study was to evaluate dichlorvos toxicity in terms of nitro-oxidative stress by determining 3-nitrotyrosine (3-NT) levels in the fore, mid, and hindbrain regions in acutely exposed rats. Male Sprague-Dawley rats were randomly allocated to three groups of eight. Group 1 was administered a single intraperitoneal dichlorvos dose of 1.8 mg kg(-1) (0.1xLD(50)) and group 2 a dose of 9 mg kg(-1) (0.5xLD(50)). The control group received 0.5 mL saline solution via the same route. 3-NT and tyrosine (TYR) levels were measured using high performance liquid chromatography with a photodiode array detector (HPLC-PDA) and expressed as a ratio of 3-NT to TYR. The 3-NT/1000 TYR ratios increased significantly in the fore-, mid- and hindbrains of the exposed groups compared to control (p < 0.01). In the forebrain, the increase was also significant between the treated groups. Our study has confirmed that acute exposure to dichlorvos leads to nitro-oxidative stress in the brain and that 3-NT may play a role in the mechanism of dichlorvos neurotoxicity.