Abstract Dense ceramics of BaPbO 3 with a perovskite-type structure were prepared via a modified oxalate coprecipitation method, controlling the starting molar ratio of Pb/Ba. Oxalate coprecipitation from a mixed nitrate solution with molar ratio of Pb/Ba ≥ 1.05 led to dense BaPbO 3 ceramics with relative density higher than 90%. This densification was due to liquid phase sintering of fine particles of BaPbO 3 with the aid of a small amount of coexisting PbO, formed by calcination of the oxalate. The coprecipitation method was also used to prepare dense Ba 1− x La x PbO 3 ceramics, and their electrical conductivity and Seebeck coefficient were measured at high temperatures to evaluate their thermoelectric power factors. The power factor for the BaPbO 3 ceramic was comparable to that for the material prepared by a press–sintering method, indicating that the present coprecipitation method is a convenient way to prepare dense BaPbO 3-based ceramics for exploring the thermoelectric properties.