Counterfeit components have been defined as a growing concern in recent years as demand increases for reducing costs. In fact the Department of Commerce has identified a 141% increase in the last three years alone. A counterfeit is any item that is not as it is represented with the intention to deceive its buyer or user. The misrepresentation is often driven by the known presence of defects or other inadequacies in regards to performance. Whether it is used for a commercial, medical or military application, a counterfeit component could cause catastrophic failure at a critical moment. The market for long life electronics, based on commercial off the shelf (COTS) parts, such as those used in medical, military, commercial depot repair, or long term use applications (e.g. street and traffic lights, photovoltaic systems), seems to create a perfect scenario for counterfeiters. With these products, components wear out and need to be replaced long before the overall product fails. The availability of these devices can be derived in many ways. For example, a typical manufacturer may render a component obsolete by changing the design, changing the functionality, or simply discontinuing manufacture. Also, the parts that are available after a design has been discontinued are often distributed by brokers who have very little control over the source or supply. Recycling of devices has also emerged as a means of creating counterfeit devices that are presented as new. And finally, as demand and price increase, the likelihood of counterfeits also increases. This paper will address the four unique sources of counterfeit components and insight into how they occur. Detection methodologies, such as visual inspection, mechanical robustness, X-Ray, XRF, C-SAM, Infrared Thermography, electrical characterization, decapsulation, and marking evaluations, will be compared and contrasted, as well as multiple examples of counterfeit parts identified by DfR.