87Sr/86Sr isotope analysis was performed on 45 cattle teeth, 5 sheep/goat teeth and 2 pig teeth from two archaeological sites in the Netherlands, dating to the Iron Age and Roman period. This makes it one of the largest strontium isotope projects focusing on animals from the Netherlands - to date. An integrated approach was taken, combining the strontium results with those from archaeology and zooarchaeology. Mobility of cattle in the Iron Age is demonstrated for five of the 23 analysed samples from the rural settlement of Houten-Castellum by strontium isotope analysis. Three animals travelled over considerable distances (over 150 km) to Houten and oxygen and carbon stable isotope values support a non-local origin for one of these animals. There is little evidence for incoming animals at this site during the Roman period with only one animal recording a non-local strontium isotope signature. In contrast, strontium isotopes indicate at least four different geographic origins for livestock in the Roman town of Heerlen, with none of the cattle being local. The results highlight the differing behaviour in the two sites. Whereas for a rural settlement like Houten, the Iron Age influx of animals might be explained by gift exchange, trade or cattle raids, it is likely that the flow of traded livestock during the Roman Period would go from rural settlement to towns and army camps. Heerlen represented the destination of animals derived from the surrounding areas to supply an active Roman town.