Vesicular coats select receptors and other transmembrane cargo and drive membrane curvature to generate cargo-loaded carriers for membrane trafficking pathways. Retromer assembles coats with several cargo adaptors to retrieve endosomal cargo to distinct pathways, including retrograde transport to the Golgi and recycling to the plasma membrane. This process of endosomal cargo retrieval is an essential regulator of protein localization and turnover, and its dysregulation has a pronounced fallout in highly specialized cells such as neurons. We use structural studies to understand how cargo recognition initiates the formation of membrane carriers bound to specific trafficking routes. A combination of cryo-electron tomography (cryo-EM) and sub-tomogram averaging (STA) has provided us with insights into the organization of several membrane-assembled retromer coats and revealed a modular nature of this coat.