ABSTRACT: A qualitative and quantitative study was carried out on the benthic foraminiferal assemblages from the upper Eocene to lower Oligocene of a section of the Caltavuturo Formation exposed near Piana degli Albanesi (northwestern Sicily). The recognized taxa are evaluated in terms of their ecology and bathymetric interpretation. Biostratigraphic constraints are defined combining both nannofossils and planktic foraminifers biozonations. The planktic-benthic foraminiferal ratio allowed the reconstruction of water depth variations. Atotal of 48 benthic foraminiferal taxawere extracted from the samples. The benthic assemblages and the P/(P+B) ratio indicate a lower to middle bathyal depositional depth, although an abrupt drop of sea level of about 140 m is recorded across the suspected Eocene-Oligocene transition. Calcium carbonate content decreases upsection, suggesting an increase in terrigenous supply in the lowermost Oligocene.