SummaryThis report describes the successful treatment of a traumatic splenic abscess by transabdominal drainage under ultrasonographic guidance. The gelding presented for investigation of recurrent pyrexia, mild abdominal pain and weight loss after a penetrating trauma to the caudolateral abdomen 5 weeks previously. At this stage, the abdominal wall had healed and a splenic abscess was diagnosed. Before treatment, mature adhesions between the abdominal wall and the spleen were confirmed by diagnostic laparoscopy in the standing horse. Transabdominal ultrasound‐guided drainage was performed, followed by intralesional placement of a balloon catheter for 2 weeks and a silicone drain for an additional week. Postoperatively, the horse was treated with intralesional and systemic antibiotics. The healing process was unremarkable and the horse was discharged 4 weeks postoperatively. At 10 months post‐surgery, after the body condition score had normalised, the horse returned to its previous level of performance.