We have measured the electrical‐transport and magnetic properties of several intermetallic compounds UTSn and UTSb, where T is a transition metal. The electrical resistivity is up to three orders of magnitude larger than usually found for U‐based compounds. This is ascribed to the occurrence of a spin polarized energy gap related to the MgAgAs‐type crystal structure. For UNiSn at least one spin band closes at low temperature, resulting in half‐metallic behavior. Interestingly, the magnetic properties exhibit Kondo‐lattice character and weak‐moment ordering.