CLEM (Correlative Light Electron Microscopy) combines the capabilities of two typically separate microscopy platforms: light (or fluorescent) microscopy (LM) and electron microscopy (EM). The advantage of LM is that it can provide wide field images of whole, often living, cells, but its resolution is limited. The advantage of EM is that it can provide much higher resolution images, up to molecular dimensions, but only over specific regions of a cell at a time and not in living cells. CLEM combines the advantages of both techniques, allowing scientists to spot cellular structures and processes of interest in whole cell images with LM and then zoom in for a closer look with EM. This dual examination provides valuable complementary and often unique information.