For the first time, transparent La0.2Y1.8O3 nanostructured polycrystalline scintillators were fabricated by sintering nanoparticle powders at high temperatures and their scintillation properties are reported. La0.2Y1.8O3 is a host material that has never been investigated as scintillators for radiation detection. Our observations found that La0.2Y1.8O3 has an intense scintillation luminescence, a detection efficiency higher than that of YAG:Ce and a comparable energy resolution to NaI and CsI scintillators. In addition, La0.2Y1.8O3 is stable and has luminescence decay lifetime in the picosecond range which is favorable for radiation detection. The luminescence of La0.2Y1.8O3 has a large Stokes-shift and a large emission bandwidth, and the luminescence is highly temperature dependent. Different from most doped scintillators, the luminescence of La0.2Y1.8O3 is most likely from the self-trapped excitons. The discovery of La0.2Y1.8O3 scintillators opens a new door for the research of new materials for radiation detection.