Acute urinary retention (AUR) is a sudden and painful condition. It occurs when a person is unable to urinate. In men, AUR is most often caused by an enlarged prostate, known as benign prostatic hyperplasia (BPH), which blocks the urethra. The first steps in treatment are to insert a catheter to empty the bladder and to start medication that acts on the prostate (an alpha-blocker). After some time, the catheter is removed during a so-called Trial Without Catheter (TWOC) to see whether the patient can urinate normally again. At present, it is unclear how long a catheter should remain in place before this trial is performed. In Dutch hospitals, the duration varies widely: in some hospitals, the catheter is removed after only a few days, while in others it stays in place for two weeks or longer. A longer catheter duration can cause more discomfort and complications, such as urinary tract infections or blood in the urine. Therefore, it is important to determine whether a shorter catheterization period is equally effective and safe compared to a longer one. The RELIEF study investigates whether a short catheter duration of three days is as safe and effective as the current average of fourteen days. A total of 478 men with acute urinary retention will participate in this nationwide randomized controlled trial. All participants will receive a catheter and start (or continue) treatment with an alpha-blocker. They will then be randomly assigned to one of two groups: one group will have the catheter removed after three days, and the other group after fourteen days. The main question is whether a shorter catheter duration is as successful as a longer one. Success means that the patient can urinate normally after catheter removal, without needing to have the catheter replaced. The study will also compare the number of complications, patients' experiences with the catheter, their quality of life, and the overall healthcare costs. By conducting this study, doctors will gain better evidence on the optimal timing of catheter removal in men with AUR. The goal is to avoid unnecessarily long catheterization, reduce discomfort and complications, and improve the quality of care for men with AUR. The results of the RELIEF study may help improve the management of AUR, making care more consistent, efficient, and patient-friendly both in the Netherlands and abroad.