Gram-negative bacterial outer membrane vesicle production and function have been studied using a variety of quantitative and qualitative methods. These types of analyses can be hampered by the use of impure vesicle preparations. Here we describe a set of techniques that are useful for the quantitative analysis of vesicle production and for preparative yields of highly purified vesicles for studies of vesicle function or composition. Procedures and advice are also included for the purification of vesicles from encapsulated and low-yield strains.