Aim: Reviewing the scientific literature with regards to urinary catheter washouts in order to prevent occlusion. Background: Patients with long-term indwelling urinary catheters often suffers from catheter blockage. Encrustations and the forming of biofilm on the catheter surface are among the most common causes of occlusion. It is unknown whether urinary catheter washout is the treatment of choice to prevent occlusion. Methods: A systematic review of the scientific literature regarding urinary catheter washouts. The study was conducted by two independent reviewers. The search used MeSH and freetext terms, in The Cochrane Database of Systematic Reviews, Academic Search Elite, CINAHL, MedLine and SweMed+, and an additional mapping of clinical guidelines in order to update praxis. Findings: The study shows that there is insufficient scientific evidence as to whether urinary catheter washouts prevent catheter blockage. Conclusion: There is insufficient evidence that urinary catheter washouts are beneficial. Individual care planning and evaluation of long-term indwelling catheter care is important in minimizing the risk of harmful side effects.