A resistivity survey was carried out at Dorchester on Thames in Oxfordshire ahead of a potential building development between 32 and 36 High Street. Two small areas were surveyed at high resolution in order to evaluate the archaeological potential of the site which is known to lie immediately to the north of the Roman town of Dorchester. Several amorphous areas of high resistance were located across two separate survey areas. The southernmost, survey Area 1, revealed high resistance associated with a swimming pool and extant land boundary. Zones of high resistance located in Area 2, to the northwest of the site, could not be confidently interpreted and although may be related to modern ground disturbance, moisture uptake and sheltering effects from mature trees, their archaeological potential should not be dismissed.