The purpose of this study was to evaluate the protective effects of fenugreek (Trigonella foenum graecum L.) upon dieldrin-induced perturbations of haematological parameters and damages to liver and kidney of male Wistar rats. Under our experimental conditions, dieldrin poisoning resulted in 1) an alteration of several haematological parameters, 2) an oxidative stress evidenced by an increase of lipids peroxidation level associated with an increase of superoxide dismutase activity and a decrease of glutathione peroxidase and catalase activities in hepatic and renal tissues, 3) increased levels of glucose, total cholesterol, triglycerides, creatinine, urea, uric acid and proteins in blood, 4) increased activities of lactate dehydrogenase, alkaline phosphatase and transaminases in blood. Previous administration of fenugreek was found to hinder these dieldrin-induced damages: all hematological, renal and hepatic biomarkers, level of lipids peroxidation and activities of catalase and glutathione-peroxidase in liver and kidney were kept close to control values. This protective effect is mainly attributed to antioxidant properties of fenugreek.