This is the first documented case of clostridial myositis in a foal. A 36-hour-old warmblood filly presented for evaluation of mild colic. The foal received two doses of intramuscular banamine prior to presentation. A firm swelling was noted over the injection sites approximately 48 hours following administration. The swellings were fenestrated, flushed with sterile saline, infused with both oxygen and potassium penicillin, and penrose drains were inserted to prevent closure. The foal was medically managed with broad-spectrum antibiotics, anti-inflammatories, intravenous fluids, and gastroprotectants. Damage to the affected region resulted in the sloughing of a 500 cm2 region of the right medio-caudal thigh. Daily wound management included flushing the wound using intralesional pulsed lavage, cold hosing, and hand walking. The course of hospitalization encompassed one month. The foal was discharged on oral chloramphenicol and gastroprotectants. The affected region healed via second intention with no evidence of fibrotic myopathy.