Wah Chiu is a pioneer in methodology development for cryogenic electron microscopy (cryo-EM). His work has made multiple transformational contributions in developing single particle cryo-EM as a tool for the structural determination of molecular machines at atomic resolution. His lab has solved many cryo-EM structures including viruses, chaperonins, membrane proteins, ion channels, antigen-antibody complexes, protein-RNA complexes and RNA in collaboration with many scientists around the world. He continues to establish high standard testing and characterization protocols for cryo-EM instrumentation and to develop new image processing and modeling algorithms for cryo-EM structure determination. His current research focuses on developing cryogenic electron tomography (cryo-ET) to determine near atomic resolution structures of molecular complexes in situ.