Numerous virus families utilize endocytosis to infect host cells, mediating virus internalization as well as traf?cking to the site of replication. The endocytic pathways utilized include clathrin-mediated endocytosis, caveolae, macropinocytosis and non-clathrin, non-caveolae pathways. The tools to study endocytosis and, consequently, virus entry are becoming more effective and speci?c as the amount of information on endocytic component structure and function increases. Now, the use of inhibitory drugs, although still quite common, often leads to non-speci?c disruptions in the cell. Molecular inhibitors in the form of domi-nant–negative proteins and siRNA have surpassed the use of chemical inhibitors in terms of speci?city to in-dividual pathways. This review focuses on the experimental approaches taken to examine virus entry and provides some examples on a variety of virus families.