Ascaris lumbricoides infection affects approximately 1.5 billion people globally. Children with environmental and socio-economic risk factors are more susceptible to infestation, with serious complications such as intestinal obstruction (IO), volvulus, intussusception, and intestinal necrosis.We present the case of a 3-year-old girl who arrived at emergency department with abdominal pain and diarrhea for the last 3 days. The previous day she took an unspecified anthelmintic. Symptoms worsened with vomiting and diarrhea, with expulsion of roundworms through mouth and anus. Physical examination revealed bloating, absence of bowel sounds, abdominal tenderness, and a palpable mass in right hemi-abdomen. Abdominal radiographs showed air-fluid levels with mild bowel distention and shadows of roundworms. The diagnosis of IO by A lumbricoides. infestation was established and surgical approach scheduled. During exploratory laparotomy an intraluminal bolus of roundworms from jejunum to ascendant colon was evident. An ileum enterotomy was performed and worms were removed. Fluid therapy and antibiotics for 72 hours were administered, with posterior albendazol treatment for 3 days. Patient was uneventfully discharged on the tenth day.Reduction in parasitic load by means of improvements in sanitation, health education, and anthelmintic treatment must be implemented in endemic zones to prevent serious life-threatening complications by A lumbricoides. infestation, because some of them require urgent surgical treatment.