The insertion of an indwelling urethral urinary catheter is an invasive procedure that is commonly undertaken in healthcare settings. However, there are several risks and potential complications associated with these devices, so their use should be avoided where possible. It is important that nurses are equipped with the necessary knowledge and skills not only to assess if a patient requires a catheter, but also to minimise the risk of associated complications and to understand how these can be managed. This article discusses some of the common complications that can occur with the use of indwelling urinary catheters, including: catheter-associated urinary tract infections; catheter blockages; encrustation; negative pressure; bladder spasm and trauma; and, in men, paraphimosis. It also explains the steps that nurses can take to reduce the risk of these complications and how to manage them effectively.