The change ∆S of the thermoelectric power of high-purity gold wires due to quenched-in lattice vacancies was measured between 4.2 and 220°K. The vacancy concentration was determined from the quenched-in electrical resistance at 4.2°K. From the value of ∆S at 200°K, where phonon-drag effects are negligible, the electronic part ∆Se of ∆S was calculated as a function of the temperature, using the Friedel theory. The phonon-drag part ∆Sg was obtained from the equation ∆Sg=∆S-∆Se. Vacancies were found to cause a reduction of the electronic part and of the phonon-drag part of the thermoelectric power. |∆Se| and |∆Sg| reach a maximum at low temperatures. The phonon-scattering cross section of vacancies, as estimated from ∆Sg assuming a pure Rayleigh-type scattering mechanism, indicates that phonons are scattered by vacancies predominantly through the strain field associated with the vacant lattice site.