New Hot Laboratory Facilities which support three major research programs directed by the Los Alamos Scientific Laboratory of the University of California are described. For the Nuclear Rocket Propulsion Program, a hot cell addition to the Radio Chemistry Building at Los Alamos will be completed early in 1963, and construction is expected to start soon on the hot cell addition to the Maintenance, Assembly and Disassembly Building at the Nuclear Rocket Development Station in Nevada. Integral hot laboratories are designed in the facilities for the Ultra High Temperature Reactor Experiment and the Fast Reactor Core Test at Los Alamos. (auth)