The normal and high pressure thermoelectric power (TEP) of three cerium compounds are compared and the origin of the differences in their behaviour is discussed. CePd 3 shows a monotonic increase in thermopower as a function of pressure up to maximum pressure studied ∼5GPa. In sharp contrast, CeSn 3 shows an increase only up to 2–3GPa and then starts decreasing. The ambient and high pressure behaviour is discussed by computing electronic structures of three Ce compounds, viz. CePd 3 , CeSn 3 and CeIn 3 using TB-LMTO method. The f-band width is larger in CeIn 3 as compared to the other two compounds, explaining the cause for its lower ambient TEP. The density of states of the f-band is maximum, narrower and the closest to the Fermi level in CePd 3 explaining its highest TEP. The band structure does not show much variation at higher compressions for CePd 3 and CeIn 3 . However, in the case of CeSn 3 , the band structure at higher compressions indicates an electronic topological transition, a possible cause for the pronounced peak TEP, observed in experiment.