Excavations were undertaken in advance of construction work at Newbury Sewage Treatment Works on the outskirts of Thatcham in Berkshire, close to the sites of previous excavations undertaken by Wymer and by Peake and Crawford. Worked flint of Mesolithic date was recovered from a sandy layer overlying river gravel in two distinct concentrations suggesting two distinct episodes. Use wear analysis of the flint suggests that the sites were used as home bases at which a wide range of activities took place, with an emphasis on the processing of plant foods. A 14C date of 9100±80 BP was obtained from a sample of hazel-nut shells from within one of the concentrations. Analysis of the soil and sedimentary sequence as well as the pollen indicates constantly changing localised environments in the early Holocene in the Thatcham area, with sporadic occupation by Mesolithic communities on the drier areas at the edge of the floodplain.