Total hip replacement arthroplasty and hip resurfacing are two of the most successful orthopaedic operations performed worldwide. Critical to the success of these operations is the accurate placement of the components. Correct component alignment reduces mechanical wear and the risk of dislocation. Traditionally, correct component alignment relies on the surgeon referencing from the position of the patient on the table and anatomical landmarks. However, it is now known that this leads to a wide variability in component position. Computer navigation systems aim to optimise component placement. The purpose of this review is to describe the different types of computer navigation systems available and their use in both total hip arthroplasty and hip resurfacing.