As a major educational and cultural Aegean city during Hellenistic and Roman times, Nysa has been the focus of archaeological investigations for the last 100 yrs. Past and ongoing excavations have revealed large ancient buildings: theatres, amphitheatres, a library, shops, etc... However, it is suspected that the original city may have extended further and little is known about the local road network. Shallow geophysical investigations may help gather crucial archaeological information to better characterize the extent and richness of the city of Nysa. We carried out a ground-penetrating radar (GPR) test study at specific sites around the city to assess the potential of that method for the detection and imaging of buried archaeological features. We collected 22 profiles at 250 MHz and 500 MHz with a Mala Geosciences RAMAC system equipped with shielded antennae. Preliminary results revealed the existence of buried walls ∼50 m west of the library. They systematically display a characteristic signature in GPR profiles and may be described in terms of location, geometry, dimensions and, to a certain extent, of construction style. Later excavations confirmed our observations and unearthed a previously unknown temple. Furthermore, we could identify remnants of the road network within the limits of the ancient city. On the basis of such positive results, future work will comprise a generalisation of GPR surveys over and around the city of Nysa to complete existing maps and precise its role and position in the Aegean region.