This study aimed to characterize the hematobiochemical and immunological profiles following immunization of equine with tetanus toxoid or/and toxin for obtaining antitetanic hyperimmune serum with special reference to the role of adjuvants in boosting immune response to immunization. Forty- Five apparently healthy horses were divided into 9 groups, one control group and other 8 groups were subjected to 8 vaccination protocols including tetanus toxoid or/ and toxin with or without adjuvants according to the experimental design of this study. Blood samples were collected from all horses and were assayed for the selected hematobiochemical and immunological parameters. Hematologically, there was a significant decreasesin the mean values of RBC, Hb, PCV, MCV and platelet in all vaccinated groups compared to control one. MCH and MCHC values showed a significant increases in immunized horses except in group administered tetanus toxoid combined with CFA whereas their values exhibited a significant decreases. The mean values of TLC, neutrophil, lymphocyte, and monocyte counts exhibited a significant increase in all vaccinated groups with or without addition of adjuvants. The results of serum biochemical parameters showed significant reduction in serum albumin levels and marked elevation in the concentrations of total protein, globulin, total bilirubin, direct bilirubin, indirect bilirubin as well as serum enzymatic activities of AST and LDH. Regarding the immunological responses, all vaccinated groups demonstrated a significant increase in the limits of flocculation, IgG and α1, α2 and γ-globulins compared to control particularly in groups injected with a combination tetanus toxoid and toxin. For most tested parameters the effects were more pronounced when CFA was added to the vaccination protocols.  In conclusion, the presented results can consider the Freund adjuvants as apotent enhancers of immune response to tetanus vaccines for production of high titer hyperimmune serum with few side effects and thus high safety margin. However, the repeated use of horses for preparation of antitetanic hyperimmune serum should be avoided as it can result in chronic inflammatory stimulus leading to various health hazards particularly on liver.