A fragment of an ursid radius with seventeen incisions (one of them incomplete) was excavated in the 1950s in the Dziadowa Skała Cave in the Częstochowa Upland in southern Poland from a deposit with faunal remains from the Eemian (ca 130–115 kyr). This object has been cited as the earliest evidence of Neanderthal cognitive abilities in the region, but it has been never studied in detail. The artefact has now been re-examined using microscopy and X-ray computed tomography. For this study we revised the determination of the bone and studied the morphology and metric parameters of the incisions (length, width, depth and opening angle). We also used experiments, statistical analysis and an analysis of the incisions' topography to establish the techniques behind their manufacture. The obtained results show that the bone was marked using a retouched stone tool, and that the incisions were produced during a single episode by a right-handed individual using repeated unidirectional movements of the tools’ cutting edge. The incisions are evidently an effect of a deliberate action, not a side-effect of some practical activity. The bear radius from Dziadowa Skała is thus yet another piece of evidence for the emergence of symbolic culture, evolved by hominins in Africa and Eurasia, and represents the oldest example of marked bone north of the Carpathian Mountains.