We report the temperature dependence of the resistivity and thermoelectric power (TEP) under hydrostatic pressure of the itinerant antiferromagnet BaFe2As2 and the electron-doped superconductor Ba(Fe0.9Co0.1)(2)As-2. We observe a hole-like contribution to the thermopower below the structural/magnetic (S-M) transition in the parent compound that is suppressed in magnitude and temperature with pressure. Pressure increases the contribution of electrons to transport in both the doped and undoped compound. In the 10% Co-doped sample we used a two-band model for thermopower to estimate the carrier concentrations and determine the effect of pressure on the band structure.