The purpose of the research was to assess the impacts of L-arginine (AR) on some biochemical indices and oxidative stress in male Wistar rats exposed to imidacloprid (IM) toxicity. Forty rats were used and they were randomly assigned to four groups. They received the treatments once daily by oral gavage for 14 days as follows: distilled water [DW group], imidacloprid (71 mg/kg) (IM group), imidacloprid (71 mg/kg) and L-arginine (100 mg/kg) [IM + AR100 group], imidacloprid (71 mg/kg) and L-arginine (200 mg/kg) [IM + AR200 group]. The rats were sacrificed after the study ended and the levels of serum proteins, urea and creatinine, oxidative stress parameters, as well as the activities of serum enzymes, were estimated. Significant reductions were recorded in the total protein concentrations of the IM and IM + AR100 groups relative to that of the DW group, respectively. Also, substantial declines were observed in the globulin levels of the IM and IM + AR100 groups compared to that of the DW and IM + AR200 groups respectively. There were significant elevations in the aspartate aminotransferase (IM, IM + AR100 and IM + AR200 groups) and creatinine (IM group) levels relative to that of the DW group correspondingly. Moreover, significant reductions were recorded in the activities of hepatic catalase and renal superoxide dismutase of the IM group compared to that of the IM + AR200 group respectively. It can be deduced that IM appreciably disrupted some serum biochemical indices probably through the induction of oxidative stress, while AR alleviated the undesirable effects of IM particularly at 200 mg/kg, perhaps through its antioxidant and bioprotective properties.