In this article we report 3 horses that developed an extraperitoneal abscess after colic surgery at the incision site. All 3 horses presented with nonspecific clinical signs and extraperitoneal abscess was diagnosed from ultrasound evaluations and cytological examination of abscess aspirates. One horse developed dehiscence of the incision after drainage of the abscess through the incision. In 2 cases a small standing paramedian incision was performed through which the abscess was drained and lavaged; complete resolution of the abscess and healing of the incision was achieved in both cases. Extraperitoneal abscess is a previously unreported incisional complication after colic surgery in horses. Early and careful ultrasonographic examination of the abdominal incision is required for diagnosis in cases with nonspecific clinical signs. A paramedian incision through therectus abdominismuscle into the abscess cavity permitted adequate drainage and debridement of the abscess in 2 cases.