Abstract Introduction: We present a case of completely obstructed anastomosis after rectal resection which was nonsurgically and successfully treated with a blunt penetration technique using a commonly used device for transanal ileus drainage. The technique we used in this case has not been previously reported. Case presentation: A 79-year-old Japanese man underwent redo rectal resection for completely separated anastomosis which was caused by anastomotic leakage after a sigmoidectomy performed 3 years previously that was remedied by diverging ileostomy. Immediately after the redo surgery, fluoroscopy showed good passage through the colorectal anastomosis but no anastomotic leakage. However, fluoroscopy and colonoscopy prior to the ileostomy takedown showed complete obstruction of the anastomosis. Unlike usual anastomotic strictures, the lumen between colon oral and rectum anal to the anastomosis was completely discontinued by a membranous structure. Therefore, a conventional balloon dilatation technique was unsuitable for this condition. We applied a blunt penetration technique using a commercially available device designed as a transanal drainage system for obstructing colorectal cancer to restore the continuity between the colon oral and rectum anal to the anastomosis. After restoring the continuity, we performed conventional balloon dilatation for the anastomosis and successfully treated the anastomotic obstruction. Subsequently, the patient underwent ileostomy takedown and is currently doing well 12 months after the ileostomy takedown