Archaeological site 3 in Ulów is in an area previously thought not to have been settled before historical times. Systematic excavation work that began there in 2002 revealed long-term occupation from the Late Palaeolithic to the Middle Ages. The majority of archaeological features represent a cemetery belonging to the Late Roman and Early Migration periods (III–V c. AD, Wielbark culture). The site’s relative chronology was determined from analyses of archaeological artifacts. To complete the chronological framework required for a proper interpretation of cultural processes, a group of charcoal fragments was selected for radiocarbon (14C) dating. These charcoals were first taxonomically identified and weighed, and then designated for accelerator mass spectrometry (AMS) and conventional 14C analyses. The datings (n=43) indicated three main chronological horizons. Some of the graves from the Wielbark culture contained charcoals of younger or older age, posing problems in interpreting taphonomic processes at this multicultural site. In the light of the 14C dating results, the chronology of several features previously attributed to the Wielbark culture was re-interpreted.