Bismuth lead oxide is a promising fast-ion conductor, with an oxygen ion conductivity in excess of 1 S cm(-1) at 590 degrees C. The characterization of the system (Bi2O3)(1-x) (PbO)(x) has previously been investigated using powder X-ray diffractometry; however, a detailed study using vibrational spectroscopy has not been carried out. This work examines the phases present between x = 0 and 1 using both infrared and Raman spectroscopy. Detailed spectra of the phases are included, as well as an analysis of those phases. In general, the phases are reasonably consistent with previously published data; however, certain aspects differ. gamma-Bi12PbO19, for example, was found to be a solid solution stable over a wide range of PbO, rather than a single phase as previously published. A summary of the room-temperature phases, after having been quenched from specific temperatures, is included in the form of a proposed phase diagram.