Biochemical and heamatological parameters in blood of Clarias gariepinus subjected to sub lethal concentrations of Tephrosia vogelii extracts for two weeks were determined. The fish species used for this study were purchased from the Ministry of Agriculture, Fisheries Division, Ogbomosho, Nigeria. The values of hematological and biochemical indices of C.gariepinus were subjected to Analysis of Variance (ANOVA) and Duncan Multiple Range Test (DMRT). No significant changes in hematological and biochemical indices such as Pack Cell Volume (PCV), Hemoglobin concentration (Hb), Red Blood Cell count (RBC), total protein and glucose level. The erythrocyte indices such as Mean Corpuscular Volume (MCV), Mean Corpuscular Heamoglobin (MCH) and Mean Corpuscular Heamoglobin Concentration (MCHC) did not change significantly. There was a significant (P‹ 0.05) increase in the level of White Blood Cell (WBC) and Cholesterol in the group that received the extract compared with the control. Introduction of T. vogelii in the open water during fishing activity may have negative impact on the physiology of the fish as manifested in the changes recorded.