Complications of celiotomy incisions were evaluated retrospectively in 274 horses that survived at least 1 month after surgery, or died or were euthanatized within 1 month of surgery, as a direct result of these complications. Horses were divided into four groups; group A, a ventral median celiotomy for intestinal disease; group B, ventral median celiotomy for nonintestinal disease; group C, repair of an umbilical hernia; and group D, celiotomy in a region other than the midline. Specific incisional complications were peri-incisional edema, drainage, incisional abscess, suture sinus, and dehiscence. Incision-related complications occurred in 30% of the horses (group A, 40%; group B 18%; group C, 7%; and group D, 88%). Complications occurred more frequently in group D than group A (P=.009), which were higher than in groups B and C (P <.00001). Incisional hernia occurred in 28 of 256 (11%) horses that survived at least 4 months and were available for follow-up. Hernia formation was more common (P <.00001) in horses that had other incisional complications (23 horses) than those without (5 horses). Serous or purulent incisional drainage, were more likely to be associated with hernia formation than was serosanguineous drainage or other incisional complications.