Transport properties of pure ytterbium have been measured under high pressure, up to 91 kbar. The thermoelectric power in the fcc phase at 31 kbar is typical of an n-type semiconductor. The resistivity and the thermoelectric power could be determined between 22 and 91 kbar in the metallic bcc phase. In this pressure range, the electron-phonon interaction is predominant in the transport properties. Both resistivity and thermoelectric power exhibit an increase of the Debye temperature by a factor 1.5.