Crustal-scale seismic reflection data, acquired in 1992 by Lithoprobe, have yielded a continuous seismic cross-section across central Alberta and provide new constraints on the nature and extent of basement controls over Phanerozoic depositional and diagenetic processes in this part of the Western Canada Sedimentary Basin (WCSB). In particular, we recognize three styles of basement influence that have distinct seismic expressions: passive topographic effects, indicated by onlap, drape and infill of basin sediments over relief on the basal unconformity; faulting of the basement and overlying Cambrian strata; and abrupt lateral facies changes of uncertain origin, vertically overlying a deep-seated tectonic boundary. Taken together, examples from the seismic profile clearly demonstrate that basement structures have exerted subtle, but significant, influence over Phanerozoic paleogeography in this part of the WCSB. Overall basement relief in this region is dominated by flexural effects associated with the Alberta Foreland Basin. However, older and more localized paleotopographic elements, with maximum vertical relief of 175 m and horizontal scales ranging from tens of metres to more than 50 km, are superimposed on the smooth basement surface. The most prominent basement high underlies the Leduc southern Alberta shelf margin on the western edge of the Precambrian Loverna Block; on the basis of onlapping relationships and systematic traveltime-difference minima with respect to the Second White Specks reflection, it appears to have been an area of positive relief from the Late Cambrian to Devonian. In the same region, the basement surface is broken up by small vertical offsets along a number of faults that appear to extend upward to the top of the Middle Cambrian Earlie Formation. One of the most striking linear features of the basin is the Rimbey-Meadowbrook reef chain, which overlies the ca. 1825 Ma Rimbey magmatic arc. In map view there is an imperfect alignment of the Rimbey-Meadowbrook trend with the aeromagnetic fabric of the basement, suggesting that if basement structures had controlled the reef orientation, the control must have been indirect in nature. However, juxtaposition of seismic images from opposite sides of the reef trend reveals a series of abrupt facies changes within Middle Cambrian to Middle Devonian strata that directly overly the Rimbey are. In addition, the top-of-base ment reflection (TBR) is less coherent and preceded by a high-amplitude, localized basement precursor (BP) event in the sediments. Deep-seated controls over the orientation of the reef foundation, and possibly over coeval fluid-circulation patterns in the basin, could explain the coincidence of these elements in the seismic profile.