Synchrotron‐based full‐field tomographic microscopy established itself as a tool for noninvasive investigations. Many beamlines worldwide routinely achieve micrometer spatial resolution while the isotropic 100‐nm barrier is reached and trespassed only by few instruments, mainly in the soft x‐ray regime. We present an x‐ray, full‐field microscope with tomographic capabilities operating at 10 keV and with a 3D isotropic resolution of 144 nm recently installed at the TOMCAT beamline of the Swiss Light Source. Custom optical components, including a beam‐shaping condenser and phase‐shifting dot arrays, were used to obtain an ideal, aperture‐matched sample illumination and very sensitive phase‐contrast imaging. The instrument has been successfully used for the nondestructive, volumetric investigation of single, unstained cells.