In the past few decades, biological processes such as protein-protein and protein-ligand interactions have been studied to atomic resolution under “near-physiological” conditions using in vitro NMR spectroscopy. With the advent of in-cell NMR spectroscopy, biological interactions can now be studied within a cellular environment to provide information at atomic resolution under physiological conditions. By performing NMR spectroscopy on living cells, we can begin to better understand the structural underpinnings of biological activity. This article will discuss the more recent advances in the field of in-cell NMR spectroscopy, both in prokaryotic and eukaryotic cells.