Details of the design, fabrication and assembly, and operating experience are given for the vacuum system of the MURA 50-MeV electron accelerator. A vacuum envelope constructed of ⅜-in.-thick aluminum alloy is evacuated to pressures of the order of 10−7 Torr by two 280-liter/sec getter-ion pumps. Viton-A elastomer gaskets are used throughout for both fixed and sliding seals.