Acute lower gastrointestinal obstruction due to colorectal neoplasm is a common clinical problem, which frequently requires emergency operation. Morbidity and mortality associated with emergency operation is relatively high, and almost all requires a multi-stage operation. Recently flexible rectal stent has been emerged as an alternative for the management of acute lower gastrointestinal obstruction due to colorectal neoplasm. Thus we analyzed the results of flexible rectal stent treatment for acute lower gastrointestinal obstruction due to colorectal neoplasm. METHODS: From June 1996 to May 1999 47 patients with acute malignant lower gastrointestinal obstruction were included in this study, medical records of these patients were reviewed retrospectively. RESULTS: Of 47 patients 19 were male and 28 were women, with a mean age of 57.3 years (33~77 years). Male to female ratio was 1:1.47. Causes of acute intestinal obstruction were as follows: rectal cancer, 17 patients; sigmoid colon cancer, 18 patients; descending colon cancer, 3 patients; ascending colon cancer, 1 patient; stomach cancer, 5 patients; gall bladder cancer, 1 patient; and uterine cervix cancer, 1 patient; and ovarian cancer, 1 patient. Stent insertion was indicated as palliative treatment in 22 patients and preoperative decompression in 25 patients. Successful stent insertions were achieved in 40 patients (85.1%). Stent insertion was successful in 20 patients (91.0%) among the 22 patients treated for palliation. Stent insertion was successfully achieved in 20 patients (80.0%) among the 25 patients. Stent insertion failure was observed in 7 patients (14.9%). Stent failed due to the complete obstruction, 3 patients; long segmental lesion, 1 patient; anatomic abnormality, 1 patient; multiple lesions, 1 patient, and ultra-low rectal lesion, 1 patient. Colonoscopy-assisted stent insertion was performed in 5 patients. Post-stent complications occurred in 12 patients among the 40 patients (30.0%): stent migration, 8 patients; expansion failure, 2 patients; fecal incontinence, 1 patient; and malposition, 1 patient. The interval between stent insertion and operation was from 1 to 30 days with a median of 7 days. Elective operations were performed as follows: anterior resection, 6 patients; low anterior resection, 7 patients; Miles' operation, 3 patients; sigmoid colostomy, 3 patients; and transverse colostomy, 1 patient. Mean distal resection margin of specimen was 2.3 cm. No postoperative complication was seen. CONCLUSIONS: Multi-stage operation can be avoided with flexible rectal stent without increasing postoperative complications. Complication rate was relatively high in patients whom stent were inserted for palliative intent. Combined colonoscopy increased the successful rate in difficult cases. Immediate operation should be considered for the patients with long segmental lesion, multiple lesions, ultra-low rectal lesion, and when perforation is suspected.