Changes in electrical conductivity can be exploited in electronic devices, such as data storage and memory technology. Complex transition metal oxides and strongly correlated systems often exhibit a metal-insulator transition (MIT), induced by pressure, temperature, dopants, oxygen vacancies concentration, other defects, or phase transition. Lead-yttrium-ruthenate solid solutions were synthesized and investigated for electrical conductivity (293-575K). A MIT was discovered when doping the strongly electron correlated conductor lead ruthenate with yttrium. The MIT was independent of temperature and occurred when 10 mol% lead was replaced by yttrium. The MIT is explained by the Mott–Hubbard mechanism of electron localization. Yttrium opens a bandgap at this critical yttrium concentration. Obviously, the small lattice expansion with increasing temperature had no measurable effect on the location of the MIT.