Archaeological excavations and watching briefs in the historic town of Dorchester-on-Thames in Oxfordshire have brought to light substantial new evidence for a cemetery just beyond the southern limit of the Roman town. So far, over 60 burials have been recorded and there may be at least as many more still to discover. Where datable, all appear to be late Roman. The area of the cemetery had been in domestic use in the earlier Roman period (1st to 2nd centuries AD) before the change of use to a burial ground, probably beginning in the 4th century, but possibly earlier, as two phases are represented stratigraphically. There was later, an early Saxon building on the site. Detailed osteological analysis sheds fascinating light on the lifestyle (and ailments) of Dorchester's Roman inhabitants and suggests close genetic links amongst at least a portion of the buried population, while stable isotope analysis, on the other hand, suggests two markedly different dietary regimes.On the High Street, just outside the northern line of Roman defences, further evidence of early Roman occupation was recovered, again replaced in the later period by burials (although only five on this site), and in this case, the area was later used for medieval occupation (backlands). This excavation sheds light on the topography of the Roman and medieval town, particularly the extra-mural Roman occupation, and hints at intensive medieval activity behind houses fronting High Street. Although the earliest phase on the site has mostly been lost to later truncation, it appears to pre-date the Roman defences (c. AD260) implying that part of the settlement, and possibly quite a densely settled area, was excluded from this protection.