A high-resolution pollen record from a 5-m-long sediment core from the closed-lake basin Laguna Piusbi in the southern Colombian Pacific lowlands of Chocó, dated by 11 AMS 14 C dates that range from ca. 7670 to 220 14 C yr B.P., represents the first Holocene record from the Chocó rain forest area. The interval between 7600 and 6100 14 C yr B.P. (500–265 cm), composed of sandy clays that accumulated during the initial phase of lake formation, is almost barren of pollen. Fungal spores and the presence of herbs and disturbance taxa suggest the basin was at least temporarily inundated and the vegetation was open. The closed lake basin might have formed during an earthquake, probably about 4400 14 C yr B.P. From the interval of about 6000 14 C yr B.P. onwards, 200 different pollen and spore types were identified in the core, illustrating a diverse floristic composition of the local rain forest. Main taxa are Moraceae/Urticaceae, Cecropia, Melastomataceae/Combretaceae, Acalypha, Alchornea, Fabaceae, Mimosa, Piper, Protium, Sloanea, Euterpe/Geonoma, Socratea, and Wettinia. Little change took place during that time interval. Compared to the pollen records from the rain forests of the Colombian Amazon basin and adjacent savannas, the Chocó rain forest ecosystem has been very stable during the late Holocene. Paleoindians probably lived there at least since 3460 14 C yr B.P. Evidence of agricultural activity, shown by cultivation of Zea mais surrounding the lake, spans the last 1710 yr. Past and present very moist climate and little human influence are important factors in maintaining the stable ecosystem and high biodiversity of the Chocó rain forest.