We developed cryo-scanning x-ray diffraction microscopy, utilizing hard x-ray ptychography at cryogenic temperature, for the noninvasive, high-resolution imaging of wet, extended biological samples and report its first frozen-hydrated imaging. Utilizing phase contrast at hard x-rays, cryo-scanning x-ray diffraction microscopy provides the penetration power suitable for thick samples while retaining sensitivity to minute density changes within unstained samples. It is dose-efficient and further minimizes radiation damage by keeping the wet samples at cryogenic temperature. We demonstrate these capabilities in two dimensions by imaging unstained frozen-hydrated budding yeast cells, achieving a spatial resolution of 85 nm with a phase sensitivity of 0.0053 radians. The current work presents the feasibility of cryo-scanning x-ray diffraction microscopy for quantitative, high-resolution imaging of unmodified biological samples extending to tens of micrometres.