To fully characterize the biology of a cell, we must know where proteins are located relative to sub-cellular structures. A fluorescence tagging approach is a very robust way to localize proteins at a sub-cellular level, but the lack of cellular context in fluorescence images and the resolution of fluorescence microscopy limits the ability to localize proteins to sub-cellular structures[1]. On the other hand, immuno-electron microscopy (immuno-EM) has high resolution, but it is limited by sample preparation and availability of antibodies[1]. The strengths of fluorescence microscopy (all proteins can potentially be tagged with fluorescent proteins) and immuno-EM (resolution of sub-cellular structures) are complementary, and thus many correlative fluorescence and electron microscopy techniques have been developed. However the precision of protein localization is limited with the currently available methods. In the last few years, new light-based microscopy techniques have been developed with almost one hundred-fold better resolution than conventional microscopes. Photo-activated localization microscopy (or PALM)[2] is one example. With this approach, individual fluorescent proteins can be localized with 10 nm resolution. The resolution of the image is comparable to that of an image acquired with electron microscopy. However, the localization of proteins relative to the sub-cellular structures is limited despite the improvement in resolution. To add subcellular context, we developed a method to preserve fluorescence in the sample embedded in plastic for electron microscopy while preserving the cellular morphology[1]. We performed super-resolution imaging on thin sections of tissues and correlated the signals to the subcellular structures revealed by electron microscopy. Using this method, we localized histones, TOM-20, and liprin to the expected organelles: the nucleus, mitochondrial membrane, and dense projection, respectively[1]. Nano-resolution fluorescence electron microscopy (nano-fEM) can be readily used to reveal the location of proteins within a cell.