The antiquity of dairying in regions considered to be marginal, such as the Western Isles of Scotland, has generated considerable debate. Complementary biomolecular methods are now available for identifying milk residues on ceramic vessels, which provides direct evidence for this practice in the past. A range of late Bronze Age and Iron Age ceramic cooking vessels were selected from two sites on South Uist, an island in the Outer Hebrides. The presence of milk proteins and lipids on a high proportion of potsherds confirms that these vessels were originally used to process dairy products. These data were integrated with evidence from the faunal remains and ethnographic accounts, in order to examine the wider significance and implications of dairy production in the Western Isles of Scotland during the first millennium BC. Further evidence from the pottery typologies and their depositional contexts were considered in order to comment on preparation and consumption practices.