The Center for Structural Molecular Biology (CSMB) at ORNL is an open access user program dedicated to advancing instrumentation and methods for determining the three-dimensional structures of biomacromolecules and their assemblies as well as hierarchical structures and biomimetic systems. The centerpiece of the CSMB is a small-angle neutron scattering instrument at the High Flux Isotope Reactor dedicated to studying biological samples (Bio-SANS). In addition, the CSMB operates a Bio-Deuteration Laboratory for cloning, protein expression, purification, and characterization of H/D-labeled biological macromolecules. When deuterium labeling is combined with SANS experimentation, data analysis and visualization, models of complex systems can be constructed that are not obtainable using other techniques. These tools will help researchers understand how macromolecular systems are formed and how they interact with other systems in living cells thereby bridging the information gap between cellular function and the molecular mechanisms that drive it.