Tetracycline (TC) is a widely used antibiotic for disease prevention and cure in humans and animal husbandry. Its interaction with bovine hemoglobin (BHb) protein is studied in this work to investigate the kinetics, and the potential in vivo toxicity of TC residue in cattle, at different reaction conditions. Spectroscopic measurements of BHb in the presence and absence of TC were carried out via UV/Visible spectrophotometer at different pH, reaction times and TC concentrations. Likewise, the sulphydryl reactivity of the CysF9[93]β sulphydryl groups of the BHb with 5,5'-dithiobis(2-nitrobenzoate), DTNB, was studied at pH 7.2, under pseudo-first order reaction conditions, as an indicator of tertiary and quaternary structural changes of the BHb in the presence and absence of TC. The observed changes in the soret peak of the UV/Visible spectra of the BHb suggest possible conformational and micro environmental changes of the BHb heme moiety with increasing pH, reaction time and TC concentrations. From the kinetic study, the sulphydryl reactivity is shown to be reversible with decrease in the apparent forward second order rate constant, k app , from 11.02 in the absence of TC to 8.358 in the presence of TC. The result obtained shows that there is a possible interaction between BHb and TC with may result to changes in the structure and consequently influence the oxygen binding affinity of BHb.