Objective: To describe a modified celiotomy to improve access to cranial abdominal structures in horses. Animals: Four horses. Study design: Short case series. Methods: Three horses with gastric impactions were treated with gastrotomies. One horse was treated for a diaphragmatic hernia with herniorrhaphy and mesh augmentation. In all horses, the ventral midline celiotomy was modified cranially with a J-incision through the body wall, along the paracostal arch. Results: The only surgical complications were midline incisional infections in all horses. Three of the four horses had good long-term outcomes; the remaining horse underwent euthanasia for reasons likely unrelated to incisional complications. Conclusion: The J-incision improved access to the stomach and diaphragm in these horses. The paracostal component healed in all cases without evidence of infection or dehiscence. Clinical significance: This modified celiotomy may be considered to improve access during gastrotomy and repair of dorsally located diaphragmatic hernias.