OBJECTIVE To describe clinical features, diagnostic methods, treatments, and outcomes associated with ingested wire foreign bodies in the abdomen of horses. DESIGN Retrospective case series. ANIMALS 16 client-owned horses with ingested wire in their abdomens that were evaluated at a veterinary teaching hospital between April 2002 and February 2013. PROCEDURES Data for each case were collected from medical records and owners and then reviewed. Differences in clinicopathologic variables between horses that did (survivors) or did not (nonsurvivors) survive to discharge from the hospital were assessed. RESULTS The median duration of clinical signs prior to admission was 5.5 days (range, 0.5 to 1,095 days). Survivors (n = 4) had significantly lower median WBC count, neutrophil count, and plasma total protein concentration, compared with nonsurvivors (12), and all survivors underwent surgical treatment. Peritoneal fluid analysis revealed suppurative or septic peritonitis in all 8 horses tested. The presence of wire was confirmed by abdominal radiography (n = 6), exploratory laparotomy (2), and necropsy (8). The median length of ingested wire was 6 cm; wire had perforated viscera in 13 horses, 10 of which subsequently developed abdominal abscesses. CONCLUSION AND CLINICAL RELEVANCE Abdominal perforation by wire should be considered a differential diagnosis for horses with peritonitis and abdominal abscesses. Radiography is useful for detection of wire foreign bodies in the abdomens of horses. Given the guarded prognosis for affected horses suggested by results of the present study, early and aggressive treatment, including exploratory laparotomy to retrieve the wire and address perforations, peritonitis, and abscesses, should be considered.