The paper discusses the environmental changes in the pile-dwelling period (5.7–3.2 ka) at the Ljubljansko barje (Slovenia) which were revealed during the study of settlement pattern and sedimentary analysis. The archaeological and radiocarbon data have demonstrated that the oldest pile-dwellings were located closer to the edge of the wetland, and the youngest were positioned closer to the central zone of the basin. The reason for the changes in the settlement pattern lies in the lake's gradual regression: The pile-dwellers at the Ljubljansko barje built their villages on the edge of the relatively deeper water zone as it regressed. The sedimentary analyses have revealed basal shell-rich marls grading upward into clays with terrigenous input, suggesting a complex lacustrine environment evolving with time into a marshland. At the Resnikov prekop site, a depositional hiatus occurs from 7.4 to 2.2 ka, following which the basin filled with terrigenous sediment delivered by streams from the hilly surroundings. Across the Ljubljansko barje at Stare gmajne and Blatna Brezovica, presumably no depositional hiatus occurred, but the pile-dwellings were located in the marsh, not far from the edge of the deep water zone. Both analyses clearly demonstrate the interdependence between the gradual regression of the lake and settlement pattern during the period of pile-dwellings. These results fail to support some alternative hypotheses that the sites on the southeastern edge lined the dry land formed by river banks feeding the barje.