Electrical conductivity at the microscopic grain level has been measured in densely sintered polycrystalline samples of LiFePO4 and Li0.99Nb0.01FePO4, using a four-point microcontact technique. The absolute value of conductivity as well as its spatial variability have been measured, and are consistent with previously reported bulk measurements. The results support the interpretation of the conductivity increase upon doping of LiFePO4 as a lattice effect. (C) 2003 The Electrochemical Society.