A two-year-old, intact female, domestic fawn-colored dwarf lop rabbit was presented with apathy and anorexia. Clinical examination revealed hypothermia, tachycardia, and abdominal pain. Routine hematology, biochemistry, radiographic and ultrasonographic examinations were performed. Radiographic evaluation demonstrated pneumoperitoneum, generalized small intestinal distention and marked focal dilation of the descending colon by amorphous and partially mineralized material. Ultrasonography confirmed the presence of free gas along with abdominal effusion. Exploratory laparotomy revealed focal perforation of the descending colon associated with mural abscess formation containing fecal material and pus. The severity of the lesions and multiple adhesions to adjacent organs (urinary bladder and uterus) led to the decision for intraoperative euthanasia. This case report describes clinical, imaging and surgical findings of pneumoperitoneum related to septic peritonitis secondary to colonic perforation in a domestic rabbit.