A more remarkable feature of the burial customs practiced by the Wielbark culture people during the Younger and the Late Roman Period and early phase of the Migration Period are distinctive barrows recorded in the right-bank Mazowsze and Podlasie, described in the Polish research tradition as Rostołty type. According to their rather general definition these are large barrows (diameter range of c. 20–60 m), some set apart by the presence of one of more of the following structural elements: internal, round core of several layers of stone, an overlying earth mound and an additional layer of stones laid over the mound, so-called “mantle” (cf. Fig. 2, 5). In earlier analyses barrows of Rostołty type most often were treated as a regional phenomenon (J. Jaskanis 1976; 2012), this despite the occurrence in Wielbark culture territory of one more area with barrow cemeteries, namely, in Pomerania and in the northern reaches of Greater Poland (Fig. 1). In fact, the tumuli of the Wielbark culture from the two zones display a close relationship, one that was pointed out at one time by R. Wołągiewicz (1977; 1986). This fact does not surprise because the area of present day northern Poland is where we have to locate the source area of the migration Wielbark culture people to south-eastern Europe, so well confirmed by the archaeological record and the written sources. The aim of the present text is thus to find out whether the appearance of the barrow cemeteries in Mazowsze and Podlasie may be interpreted as an expression of translation of certain elements of the burial tradition by the migrating Wielbark culture communities. The first requisite step towards grasping the relationship between the barrow cemeteries of northern and eastern Poland was determining the chronological frames of their use. Chronological analysis of the precisely dated cemeteries showed that, except for the cemetery at Nowy Łowicz, the youngest burials from northern Poland have a dating of phase B2/C1–C1a, while the earliest burials in eastern Poland date from stadium C1b. Also known from both these zones of Wielbark culture settlement are assemblages with artefact dated within the broader frames of phase C1 indicating that the date of the decline of the barrow-building tradition in Pomerania may be moved to stadium C1b (cf. Fig. 7), and the time of appearance of the first tumuli in Mazowsze and Podlasie – to stadium C1a (cf. Fig. 8–9). This surmise becomes more plausible once we include in our analysis flat graves, for example, those at Odry (Pomerania) which are dated at least until stadium C1b, and at Cecele (Podlasie) as early as starting from phase B2/C1–C1a. The chronology of barrow cemeteries presented here corroborates the argument that Wielbark culture communities migrating from northern Poland carried the custom of barrow-building to the eastern region. This hypothesis had to be tested by studying the similarities and differences displayed by the barrow cemeteries known from the two settlement zones of Wielbark culture. The analysis focused on several questions: the siting of the cemeteries, their surface area, number of barrows in a cemetery, presence of flat graves between the barrows, use of the cemetery space, barrow size and construction design, burial rite and grave goods models. The result of the study was identification of a series of similarities shared by the barrow cemeteries of northern and of eastern Poland. One example would be two models of siting of the cemetery observed in both zones: the first, near rivers, and at the same time, at a relatively small elevation above the floodplain, the second, at some distance from the watercourse, on a prominent elevation (Fig. 11–13). Similarities are observed also in the main rules of construction design of the tumuli, as is shown e.g., by the presence of stone circles around the cores (type 4 acc. to Wołągiewicz; cf. Fig. 16, 24) or at some distance from them (type 5; cf. Fig. 16, 18). Also recurring in the northern and the eastern zone of barrow cemeteries are elements of the burial rite: the occurrence of graves in the so-called flat areas (Fig. 14), bi-ritual character of most cemeteries, identical types of cremation and inhumation graves (also of the more rare types, as e.g., burials in the form of a cremation spread out in a layer at the base of the barrow) or the remains of similar ritual activities (ritual hearths; Fig. 30). Analysis of the grave inventories, unfortunately rather limited due to the destruction of many tumuli, reveals similar models of grave furnishings as well as differences in their wealth, both in northern and in eastern Poland. At one end of the scale are burials without grave goods altogether or with their limited selection (cf. Fig. 8, 9), at the other end - graves with elaborate inventories intimating the connection of the dead individual to the ruling elite (cf. Fig. 31–33). Next to the prevailing similarities shared by the barrow cemeteries in northern and eastern Poland in some specific aspects differences are also visible. Most notable is the different frequency of specific features of the barrows in the two zones, something that is well apparent during the analysis of their size and construction design. In northern Poland the dominant form is a small mound (less than 15 m in diameter) with a stone core covering almost the whole base of the barrow, whereas in eastern Poland the prevalent form is a large tumulus (over 15 m in diameter) with a visibly domed and centrally situated core. In Pomerania and in Greater Poland barrows with a stone core are encountered only exceptionally, but despite this it is possible to indicate a series of constructions which presumably are their prototypes (cf. Fig. 19, 20). We mean here arrangements in the form of flat stone pavements surrounded by a stone circle, or pavements and circles covered by earth mounds which resemble in their form the construction of mounds known from Mazowsze and Podlasie. This suggests that differences between northern and eastern Poland may have been caused by evolutionary change at work in the burial ritual of the Wielbark Culture people during the Younger Roman Period. The comparison made of Wielbark Culture barrow cemeteries recorded in northern and eastern Poland presented here definitely does not exhaust this complex and until now very superficially understood problem. But it does indicate without ambiguity the close relationship of barrow cemeteries from their two zones of occurrence and undermines the legitimacy of isolating a regionally confined Rostołty type. What is more, a closer look at the criteria used in separating this type makes it evident that a large group of barrows, assigned in earlier literature to Rostołty type, do not meet one, or even several, of the criteria. We mean here first of all small mounds with a several layers of stone covering nearly the entire base of the tumulus (cf. Fig. 18:2, 24), not infrequently laid over a grave containing only average grave goods, showing the greatest similarity to Wielbark culture barrows known from Pomerania and Greater Poland.