The Selection of a custody metering system for crude oil/products is a multilevel approach. As the Metering technology, process conditions, procurement strategies, national requirements, project time schedule and other specific project requirements are influencing each other, it is important to be aware of the interdependence of the a.m. mentioned factors. Consequently a systematic approach is required to select the optimal flow meter technology and configuration. Client and engineer shall be open-minded regarding the metering technology as a dogmatic hold to a conservative solution might turn out as the most expensive one. This holds also true for the calibration and recalibration procedure. In this respect the configuration of the metering system provides a number of potential options. Also the requirements of the national authorities and standards, accuracy requirements, availability consideration, calibration and recalibration procedure are influencing the selection of the optimal solution. It is important to commence the metering approach at an early stage with a selection study. The availability of companies, which can supply the preferred configuration, might be limited and one thing should be avoided - and your procurement department will agree - to be trapped having only one potential supplier. Further project specific requirements such as limited space, Client’s preferences, Billing and Leak Detection System requirements might also play a role in the selection process. Engineer and Client should work close together in order to set the priorities and to come to a final conclusion.