Effects of 200–450‐keV proton bombardment on the electrical properties of Pb0.76Sn0.24Te were studied.p‐type samples of initial hole concentration in the low 1017/cm3range were converted tontype after a proton dose of 5 × 1013p/cm2. For samples of higher initial hole concentration, the conversion was less consistent. The change in mobility due to bombardment was found to be moderate. The mobilities of somep‐type samples were doubled after type conversion.