RESUMEN
UNLABELLED: Nowadays appendicitis is the leading cause of acute surgical abdomen. It occurs mainly between the first and third decade of life and is very rare in the neonatal period. The pathophysiology and clinical manifestations differ from the typical signs and symptoms, making it difficult to diagnose, which is in mostly cases at the time of surgery, and 74% of them appear with perforation and peritonitis. During the first day there were no complications; however, antibiotic therapy was initiated due to the risk of sepsis. On the next day there were changes in vital signs, fresh blood by nasogastric probe, acute abdomen data, cyanosis, and decreased tone. CASE DESCRIPTION: A newborn male of 34.3 weeks gestation using the Capurro method, Apgar score 8/9, obtained by emergency caesarean section, in which the maternal abdominal cavity was with copious purulent material and perforated appendix with generalized peritonitis. Surgery was determinate, where they found necrotic ileum and appendix with five perforations in total, so resection and ileostomy was performed. Intubation and dopamine support were required, but removed within a short time, beginning oral alimentation.