To intervene efficiently in protecting the archaeological heritage it requires precise information, as well as the exact location, the limits of the site or the geomorphological features of the area. As such, an interdisciplinary research based on non-destructive, complementary methods of investigation, which can provide precious information on the underground archaeological remains, is required. The most convenient (affordable) prospection methods employed by archaeologists are, on the one hand, surface research (fieldwalking), which provides the data necessary for a chronological setting, and, on the other, air photography, which offers the possibility to identify the buried structures. The present paper focuses on the use of oblique air photography in the study of prehistoric sites and a case for generalising such practices in archaeological research, with reference to preliminary results obtained for a number of sites from north-eastern Romania.