The Northeastern Collaborative Access Team (NE-CAT) is funded by its member institutions and the National Institute of General Medical Sciences (NIGMS) to operate synchrotron X-ray beamlines to address technically challenging problems in structural biology. These beamlines are an important resource for NE-CAT's institutional members as well as the national research community. NE-CAT provides 50% of the available beam time to the national user community. These beamlines have been developed using the extremely high-brilliance x-ray sources provided by the novel dual-canted undulators of the Advanced Photon Source (APS) at the Argonne National Laboratory.The optical trains for NE-CAT’s two canted-undulator beamlines are shown schematically. Both undulator beamlines, 24-ID-C and 24-ID-E, are in full operation providing exceptionally stable well collimated X-ray beams and are optimized for microdiffraction crystallographic research. The 24-ID-C beamline is a variable-energy beamline providing x-rays from 6.5 to 20 keV. The 24-ID-E beamline is a fixed–energy microdiffraction beamline providing x-rays at 12.66 keV.