Radio Immune Assay (RIA) is an extremely sensitive in vitro assay technique to measure concentrations of antigen viz. hormones in biological fluids using antibodies. The present study reports the status of total triiodothyronine (TT3) and total thyroxine (TT4) in Trypanosoma evansi infection in a dog, year 2022. An adult, non-descript, male dog was referred to the Department of Veterinary Nuclear Medicine, Mumbai Veterinary College, (MAFSU), Parel, Mumbai (India) with a history of inappetence, weakness, and ataxia of the hind limbs. Inspection revealed cachexia, anemia, bedsores, and mild mucopurulent ocular and nasal discharge. Clinical examination revealed pyrexia, polypnoea and tachycardia. There was an enlargement of popliteal, prescapular, and submandibular lymph nodes. The blood smear examination revealed severe infection of extracellular T. evansi. Laboratory investigations showed an altered haemato-biochemical profile. RIA-enabled thyroid hormone profile revealed a reduced concentration of TT3 (0.57 nmol/l) and TT4 (22.52 nmol/l). The present study reports a reduction in the concentration of TT3 and TT4 in a dog suffering from trypanosomiasis. The drop in TT4 concentration was within the normal limit, this could be a cause for the non-appearance of usual clinical symptoms of hypothyroidism in the present case.