With the aim of applying the phase‐contrast X‐ray imaging technique to biomedical imaging, we have been developing a large‐area imaging system based on a skew‐symmetric two‐crystal X‐ray interferometer. This latest of our imaging systems has a 60×30‐mm field of view and has been used to observe fine two‐ and three‐dimensional images of several biological samples by using a 17.7‐keV synchrotron X‐ray beam at the Photon Factory. In this paper, we give the outline of the imaging system and recent observational results of large biological samples. © 2004 American Institute of Physics