Acute urinary retention (AUR) is more than ten times more common in men than women. In men it tends to occur in the elderly; the risk of AUR is higher in men > 70 years. The causes in men can be divided into precipitated or occurring spontaneously. These can be further divided according to the mechanism i.e. obstructive, neurological and myogenic. Spontaneous AUR, caused by progression of BPH leading to a mechanical obstruction of the bladder outlet, is the most common cause of AUR. The typical presentation of AUR is a patient complaining of a sudden inability to urinate associated with progressive abdominal distension which is usually painful. The pain increases in intensity with increasing distension of the bladder. An abdominal examination should reveal a distended bladder which can be confirmed by a dull percussion note. A digital rectal examination is vital to gain information on prostatic enlargement (benign or malignant), faecal load in rectum, anal tone and presence of other masses. Urinalysis and culture should be carried out on a sample obtained after catheterisation to rule out infection. Renal function should be assessed to see if there has been damage to the upper tracts. It is better not to perform a PSA test in this situation as it will invariably be raised due to distension of the bladder and catheter insertion. If catheter insertion fails then a urological consultation is required for insertion of a suprapubic catheter. Admission is essential if the patient is: unwell with urosepsis; has abnormal renal function needing investigation and fluid monitoring; has acute neurological problems; or cannot take care of the catheter. Trial without catheter needs to be planned and the ideal time to do this is within 2-3 days so that the patient can pass urine naturally.