Values of ionic transport numbers and ionic mobilities were determined for the fused system KCl-PbCl₂. Cation transport numbers of 0.24 (525°C) and 0.78 (850°C) were found for PbCl₂ and KCl, respectively. In each mixture studied t_- deviated positively and both t₊ and t₊₊ deviated negatively from linearity when plotted against equivalent fraction. The initial very rapid depression of total equivalent conductance from that of pure KCl, caused by addition of small amounts of PbCl₂, was found to be due to the depression of the ionic conductance of K+ rather than complexing between Pb⁺⁺ and Cl^- as had been previously supposed. Values of 0 were comp~red with those in the system LiCl-PbCl₂, calculated from available literature data.