Non-invasive assessment of coronary artery patency has been attempted with different imaging modalities over the last few decades. The continuous motion of the heart, the respiratory movement, together with the small and tortuous nature of the coronary arteries, made this a technically challenging task. Over the last decade, significant advances in computed tomography (CT) technology helped CT coronary angiography (CTCA) to evolve as a non-invasive alternative to conventional catheter based coronary angiography. Clinical experience with CTCA has since grown rapidly and led to its acceptance as a useful diagnostic technique for coronary artery disease in certain patient populations. Recently, there has been exponential growth in the availability and use of CTCA in several centres across the world. In order to appreciate the potential impact of CTCA on current clinical practice, it is important to understand its advantages and limitations and its clinical performance in comparison with established techniques.