Live cell imaging techniques are now essential for capturing chromosomal segregation in fertilized eggs. Although better spatiotemporal resolution of fluorescence observations could provide more information, higher phototoxicity may occur. Super-resolution microscopy is generally considered unsuitable for live cell imaging because of the considerable cell damage. Here, we developed a method for counting chromosomes in mouse living oocytes and early embryos using super-resolution microscopy based on disk confocal photon reassignment microscopy (OPRA). In this chapter, we describe the imaging conditions for minimally invasive, high-resolution observation of mouse oocytes and embryos and a method to count chromosomes via CRISPR/dCas-mediated live-cell fluorescence in situ hybridization.