Based on migrant and winter specimens, 2 separate populations of Knot Calidris canutus are shown to occur in the Netherlands. Both are sufficiently differentiated to deserve recognition on subspecies level. Breeding range, migration routes, and winter areas of both these subspecies are defined. Additional material proves that at least 3 other populations of Knot occur in the Holarctic, at least 2 of these warranting recognition as separate subspecies, but breeding grounds and winter areas are not known for all of these. Morphometrical characters and a map with migration routes for all 5 Knot populations are provided.