The objective of this study was to assess the risk of genotoxicity of d-phenothrin by measuring the oxidative stress it causes in rat liver and kidney. The level of 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG)/10(6) 2-deoxyguanosine (dG) was measured by using high performance liquid chromatography (HPLC) with a diode array (DAD) and an electrochemical detector (ECD). Sixty male Wistar albino rats were randomly divided into five experimental groups and one control group of 10 rats/group. d-phenothrin was administered intraperitoneally (IP) to the five experimental groups at 25 mg/kg (Group I), 50 mg/kg (Group II), 66.7 mg/kg (Group III), 100 mg/kg (Group IV), and 200 mg/kg (Group V) for 14 consecutive days, and the control group received only the vehicle, dimethyl sulfoxide (DMSO). DNA from samples frozen in liquid nitrogen was isolated with a DNA isolation kit. Following digestion with nuclease P1 and alkaline phosphatase (ALP), hydrolyzed DNA was subjected to HPLC. The dG and 8-oxodG levels were analyzed with a DAD and ECD, respectively. In the experimental groups, the mean 8-oxodG/10(6) dG levels were 48.15 +/- 7.43, 68.92 +/- 20.66, 82.07 +/- 14.15, 85.08 +/- 28.50, and 89.14 +/- 21.73 in livers and 39.06 +/- 7.63, 59.69 +/- 14.22, 61.13 +/- 17.46, 65.13 +/- 23.40, and 72.66 +/- 19.04 in kidneys of Groups I, II, III, IV, and V, respectively. The mean 8-oxodG/10(6) dG levels in the control groups were 44.96 +/- 12.66 for the liver and 39.07 +/- 4.80 for the kidney. A statistically significant (p<0.05), dose-dependent increase in oxidative DNA damage was observed in both organs of animals exposed to d-phenothrin when compared to controls. Furthermore, the liver showed a significantly higher level of oxidative DNA damage than the kidney (p<0.01). In conclusion, d-phenothrin administered to rats intraperitoneally for 14 consecutive days generated free radical species in a dose-dependent manner and caused oxidative DNA damage in the liver and kidney. (c) 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 607-613, 2015.