Postoperative urinary retention (UR) is a common complication following haemorrhoidectomy. This report presents a female patient who developed long-lasting UR after haemorrhoidectomy and internal sphincterotomy, which progressed to renal failure. The precipitating cause was represented by a non-healing anal ulcer and excruciating anal pain at evacuation. An unhealed anal wound, an inappropriate low-fibre diet, and excruciating anal pain commonly represent the key factors initiating the sequence ending into UR. History, presentation, diagnostic work-up, and treatment for this patient are described.