Macroautophagy is a conserved catabolic process observed in all eukaryotic cells, during which selected cellular components are transported to and broken down within lysosomes. The process starts with the capture of unnecessary material into autophagosomes, which is followed by autophagosome-lysosome fusion to generate autolysosomes that degrade the cargo. In the past quarter-century, our knowledge about autophagosome formation almost exponentially increased, while the later steps were much less studied. This fortunately changed in the past few years, with more and more publications focusing on the fate of the completed autophagosome. In this review, we aspire to summarize the current knowledge about the molecular mechanisms of autophagosome-lysosome fusion. (C) 2019 Elsevier Ltd. All rights reserved.