Analysis of hematological and biochemical parameters, including oxidative stress indicators, is an invaluable tool in wildlife health assessment, particularly for threatened or endangered species. This study was aimed at obtaining baseline information of oxidative stress indicators in eastern Pacific green turtles (
Chelonia mydas agassizii) from a relatively undisturbed habitat at Bahía
Magdalena, Baja California Sur, Mexico. Tissues were analyzed for superoxide radical (O
2
−) production, lipid peroxidation (measured as thiobarbituric acid reactive substances, TBARS), and antioxidant enzyme activity (superoxide dismutase (SOD), catalase (CAT), and glutathione
S-transferase (GST)). Overall levels for all variables were within ranges reported for other reptile species. Results suggest differences in oxidative metabolism among tissues (
p ≤ 0.05). Liver, lung and muscle had the highest levels of O
2
− production. Liver revealed the highest TBARS levels. Liver and muscle showed the highest SOD activity, while liver and kidney had the highest CAT and GST activities. These data provide baseline values of the oxidative stress indicators in tissues from eastern Pacific green turtles. Development of a biomarker system to assess the health of wildlife species, especially one that could detect early exposure to environmental pollutants or emerging diseases, would provide a useful tool in the long-term conservation of the species.