New methods permit archaeologists to distinguish between wild boar and domestic pigs with greater confidence than has been hitherto possible. Metrical methods are the most commonly used; these are reviewed. Assemblages containing a wider range of measurements (as measured by the coefficient of variation [V]) than is found in one population suggest that two populations of different-sized pigs were present, probably indicating separate wild and domestic populations with little or no interbreeding. These assemblages, sometimes taken to indicate animals ‘intermediate’ between wild and domestic, are clear evidence of full domestication. Other traditional means of diagnosing domestication based on age at death (the killing of many young animals) and biogeography (the export of the animal beyond its natural range, especially to islands) are particularly problematic when applied to pigs. New methods include the frequency of Linear Enamel Hypoplasia, which may increase due to domestication-induced stress, the study of diet through isotopes and dental microwear, and the examination of population histories through ancient and modern DNA and geometric morphometrics. These are all promising but should not be considered in isolation: many problems remain.