This case report discusses a 46-year-old female with no prior surgical history who presented with severe abdominal pain and generalized tenderness. She was found to have a small bowel obstruction secondary to internal hernia caused by a rare congenital pelvic peritoneal defect in the Pouch of Douglas. She required diagnostic laparoscopy and repair of the pelvic peritoneal defect. Congenital peritoneal defect is an extremely rare cause of small bowel obstruction but should remain a possible differential diagnosis in patients with virgin abdomen presenting with acute abdominal pain.