Flow assessment is an integral part of the comprehensive evaluation of the cardiovascular system. Cardiovascular magnetic resonance is well suited for flow assessment due to its non-invasive, multi-plane imaging capability unrestricted by windows of access and its ability to measure blood flow and velocity. Phase-contrast velocity mapping for flow assessment has been incorporated in all commercial scanners. It is versatile, and with appropriate hardware, software and expertise, it should be accurate and reproducible. In this article, we briefly describe the technique and indications for its use in current clinical practice. We suggest some practical tips in using the technique and describe some of the potential sources of errors and ways to overcome them. Finally, we provide several clinical examples demonstrating how to use phase-contrast velocity mapping in a number of acquired and congenital cardiovascular conditions.