Corynebacterium pseudotuberculosis is a gram-positive bacterium that affects several animals, including horses. The present report presents a case of a 10-year-old male West African Dongola horse that developed an external abscess caused by C. pseudotuberculosis in the Zoological Garden, University of Ibadan. The patient was presented to the garden veterinary clinic with a complaint of lameness, pus discharge, and swelling on the right forelimb. The pulse rate and temperature were within normal range. Blood was collected from the jugular vein for a complete blood count (CBC) and serum chemistry. A pus sample was collected and subjected to bacterial culture, gram staining, biochemical tests, and an antimicrobial susceptibility test. Corynebacterium pseudotuberculosis was isolated and identified in pure culture from aspirates of the pus discharge based on cultural, gram-staining, and biochemical characteristics. The organism was sensitive to gentamicin, amoxicillin, and ciprofloxacin. A warm compress, wound irrigation, and bandage were applied to the infected area. The antibiotics used were a combination of amoxycillin and gentamycin injections. Other drugs used include tetanus toxoid injection, tetanus antitoxin injection, and diclofenac sodium injection. The therapy was successful, and the patient completely recovered. Good sanitation and prompt wound care are recommended.