Abstract In the past, junction construction technology has driven the design of multilateral wells. This practice has led to technical successes that may or may not have met all of the operator's desired well objectives. These projects have often been regarded as less than successful from an economic point of view. This regard is partly due to the way that junction construction has been viewed. Junctions are presently classified by looking at the technical differences in how they are constructed, such as TAML levels (Technology Advancement – Multi Laterals)1. Although this method is suitable for looking at junction construction complexity, it does not address directly what the junction does in service. Another approach would be to drive the design using information about reservoir/production requirements. Looking at functional groups of junction features will allow the drilling or completions engineer to make sense of the myriad of available junction systems. This technique can help optimize the multilateral junction type selection for a given project. The process of planning multilateral projects from conception through well design will be discussed with a focus on using a functional classification map to clarify the junction requirements. The Functional Classification Method will assist engineers in comparing equipment options. This comparison is accomplished by, first, defining the reservoir and economic drivers, and, then, by selecting the appropriate junction attributes. Furthermore, the method will provide a process for assembling the data required to prepare the final well design and to prepare precise tender documents. To illustrate this method, recent examples from the Middle East will be presented.