There are now many physicians, both radiologists and cardiologists who are reporting CT coronary angiography (CTCA) scans who may not be aware that there are many pitfalls present. For the inexperienced reader a significant stenosis in a coronary artery can be easily missed or a moderate stenosis overcalled as significant. Artifacts can also be misinterpreted as representing a significant lesion. It is important that the studies are correctly interpreted, especially as the reported high negative predictive value of CTCA scans is a major strength of this imaging technique. The learning curve of reading these scans is steep and access to conventional coronary catheterisation results is essential for feedback and to improve the readers results. We have developed some rules to aid beginners avoid some of the pitfalls that can occur as these studies are not as easy to read as they may appear initially.