Results of sedimentological and palynological analyses and ¹⁴C dating of organic lake sediments of a transect through the basin of Phlious, west-southwest of Corinth (NE-Peloponnese, Greece) are presented. They provide a record of five moist and temperate phases, rich in predominantly deciduous Quercus and Pinus with minor representation of other deciduous and evergreen trees including evergreen oak and shrubs, interrupted by five drier and cooler episodes including Heinrich event (HE) 5, during a period of relatively high but fluctuating lake levels within Marine Isotope Stage 3 (MIS 3). The youngest interstadial of the Pleistocene pollen sequence is correlated with GRIP Greenland Interstadial 9 (GI9) with a calibrated age of around 40,000 years BP ( ¹⁴C 34,440 yrs BP). In the uppermost part of the Pleistocene sequence the occurrence of HE 4 is rather probable. This initial Pleistocene record from southern Greece is compared with those from central Greece to provide a regional synthesis of vegetation and climatic variation during this part of the last glacial period.