The Heavy Ion Cancer Therapy Accelerator facility (HICAT) for the university hospital in Heidelberg is now under construction and will be completed in 2006. The facility consists of 2 ion sources, low-energy beam transfer lines, a linear accelerator, a medium energy beam transfer line, a synchrotron, high-energy beam transfer lines, and 3 treatment locations. One of the treatment locations will be equipped with a gantry. All magnets were designed at GSI. The design of the magnets will be reviewed. Wherever possible, a conservative design approach was used. Special design efforts were necessary for the huge 90° gantry dipole and the tiny internal quadrupoles for the IH-type drift tube linac, so that prototypes of these magnets were built and tested. The design, construction, and measurements of the quadrupoles for the IH-type drift tube linac will also be discussed in detail.