The commercial development of bitumen production by cyclic steam stimulation in Cold Lake, Alberta, Canada has prompted the need to acquire relevant capillary pressure and wettability data. The USBM method was used to determine the wettability of four adjacent Cold Lake Clearwater cores at 40 o C using a heated centrifuge. A centrifuge core holder that provides confining pressure and enforces zero outlet capillary pressure was used to perform the tests. Heating was necessary to mobilize the viscous bitumen (50 Pa s at 20 o C). The theories of Hassler and Brunner [Hassler, G.I., Brunner, E., 1945. Measurement of capillary pressures in small core samples. Trans. AIME, 160, 114-123.] and Rajan [Rajan, R.R., 1986. Theoretically correct analytical solution for calculating capillary pressure-saturation from centrifuge experiments. SPWLA 27th Annual Logging Symposium (Jun.), pp. 1-17.] were used to interpret capillary pressure from the test data. One core that was unaltered was weakly water-wet. The other three cores were pre-flooded at 280 o C with large pore volumes (>8) of bitumen and brine either as a co-injection mixture (1:1 and 19:1 bitumen to brine) or as alternate slugs. Their final wettability state was water-wet to strongly water-wet. This work shows that field cyclic steam stimulation promotes water-wetness after large throughput of bitumen and brine.