Four patterns of CaCO3 abundance occur in cores retrieved from the eastern equatorial Pacific during the Venture 01 expedition. Core locations lie along a north-south transect at 110¿W underneath the different currents of the equatorial current system and along an east-west transect from 110¿ to 90¿W, at approximately 3¿S, underneath the South Equatorial Current. The ''classic'' or central equatorial Pacific pattern of CaCO3 abundance maxima associated with glacial stages as defined by the Δ18O record characterizes only a small portion of the area studied. In the area where the Peru current turns west to join the South Equatorial Current, the carbonate record is characterized by a broad low, centered on interglacial carbonate stage B-3 (approximately stage 5 in Δ18O stratigraphy) overlying a broad mid-Brunhes maximum. Low-amplitude variations in CaCO3 percentages are superimposed on this pattern. This pattern extends westward in a long-wavelength pattern in which the B-3 carbonate low becomes decreasingly pronounced away from the equator. The fourth pattern, observed north of 10¿N, is erratic and may be only local in extent.