ABSTRACT The goal of Structural Biology (SB) Core (formerly X-Ray Crystallography Core) is to provide access to expertise as well as state-of-the-art equipment and software to Center laboratories that address structural questions within their research. Understanding the biological processes involved in tumorigenesis has increasingly benefitted from structural investigations that provide key functional and mechanistic insights, as well as atomic-level details important for drug discovery. Many of the questions require the structure determination of large proteins, assemblies and macromolecular machines. The Core maintains in house equipment (Rigaku Micromax 007hf diffractometer and Titan Krios-Gatan K2 cryo electron microscope) and computational resources for data collection, processing and structure determination, including graphical workstations and a high-performance Linux cluster. The SB Core implements a range of software packages for structural determination and analysis, participates in multi-institutional consortia for access to synchrotron beamlines and cryoEM and provides training and assistance to users. In addition, the Core Head collaborates with non-structural MSK groups on macromolecular crystallization and structure-determination projects, and also provides modeling expertise and guidance to those labs that can benefit from the use of available structures in the design and interpretation of experiments. The SB Core has supported 9 investigators in the past year and has contributed to 127 publications of investigators from 3 programs.