Schipluiden (3630-3380 cal BC), the earliest known year-round settlement in the Rhine- Meuse Delta in the Netherlands, is a key site for addressing the nature of Neolithic subsistence in the wetlands of northwestern Europe. A preliminary zooarchaeological study suggested that cattle husbandry was a major activity at Schipluiden. In contrast, stable carbon and nitrogen isotope analyses of human remains from the site indicated a marine-oriented diet, implying that the Mesolithic-Neolithic dietary transition continued well into the mid-4th Millennium BC in this region. Here, we re-investigate the role and nature of cattle husbandry at Neolithic Schipluiden using mortality profiles and stable isotope analysis (δ18O, δ13C, δ15N) of animal bone collagen and tooth enamel. The age-at-death analysis suggests that cattle were managed for both meat and milk production. The δ18O and δ13C analysis of tooth enamel provide evidence that calving spread over five-and-a-half-months, which would have led to a longer availability of milk throughout the year. Cattle were grazing in open, marshy environments near the site and winter foddering was practiced occasionally. The faunal isotopic data also reveal that the high 15N in human bone collagen is more likely to signal the consumption of products from cattle that grazed on 15N-enriched salt marsh plants around the site, rather than a marine-oriented diet. This undermines the previous interpretation of the dietary practices at Schipluiden by showing that human diet in mid-4th millennium BC Rhine- Meuse area was fully "Neolithic", based primarily on products from domesticates, especially cattle, with some input from wild terrestrial and aquatic resources available in their surroundings, contrary to what has been proposed before. Collating these results demonstrates a high level of investment in cattle husbandry, highlighting the social and economic importance of cattle at the lower Rhine-Meuse Delta during the 4th millennium BC.