Butrint, a World Heritage Site in southern Albania, encompasses 3000 years of Mediterranean history from the Hellenistic Greeks to the Venetians. In Roman times a suburb of Butrint spread out across the marsh plain to the south of the city, where approximately 20 ha have been surveyed with a fluxgate gradiometer, and 4 ha with a ground resistivity meter. The magnetic anomalies show that the line of the aqueduct into the centre of Butrint is evident for part of this area, but the aqueduct signature becomes progressively less distinct on approaching the Vivari Channel, probably owing to deeper burial. A complex of confused, short-wavelength anomalies, but with some linear elements covers about 3 ha and is associated with exposed building remains. The abrupt termination of these anomalies to the west may be associated with the former Roman water front. Isolated smaller areas of magnetic anomalies up to 0.5 ha in the area surveyed, show buildings and associated ditches away from the main complex. The resistivity survey allows some detailed constraints on the position of buildings in the densely occupied area. Analysis of the orientation of linear anomalies indicates there are two co-genetic sets of magnetic and resistivity linear anomalies. A strong NW–SE and weaker NE–SW set, which parallel the aqueduct and the alignment of standing walls. This set appears to indicate a regular building alignment across the whole site, which is reflected in the orientation of the few current standing walls on the site. This set may post-date the building of the aqueduct, because these reflect the latest standing remains on the site. A second stronger set of E–W and (subsidiary) N–S linear anomalies may signify either an early system of streets, or perhaps an agricultural-based ditch system developed prior to the buildings on the site. This second set may pre-date the building of the aqueduct in the first century BC, when Butrint became a Roman colony. An alternative interpretation suggests part of the suburbs street plan may be based on a non-conventional triangular network of roadways, the design of which may have been emulated in the construction of the medieval Triangular Castle.