The development of a new technique for the measurement of conduction electron g-factors from the de Haas-van Alphen effect is reported. The technique is based on analysis of the harmonic content in the oscillation waveform and has been used to study the g-factor of the neck orbits in the noble metals. The results in copper have been combined with earlier spin-splitting zero data for the belly orbits to determine for the first time the anisotropy of the local ^-factor g(k) over the Fermi surface. Some preliminary g-factor measurements in potassium are also described. The results show a large (/-shift from the free electron value which is attributed to the presence of many body effects, giving a value of — 0.29
6
± 0.02 for the Landau coefficient B
0
.