Energy resolution and detection efficiency were compared between new scintillators, lanthanum bromide (LaBr3:Ce) and lanthanum chloride (LaCl3:Ce) with conventional detectors, sodium iodide NaI(Tl) and cadmium zinc telluride (CdZnTe or CZT). The study has shown that LaBr3:Ce and LaCl3:Ce scintillator detectors provided by Saint-Gobain offer better resolution than NaI(Tl) detector. LaBr3:Ce and LaCl3:Ce detectors could resolve some closely spaced peaks from 133Ba and 152Eu, which Na(I) could not. LaBr3:Ce has slightly better resolution and higher efficiency than LaCl3:Ce. An overall advantage of LaBr3:Ce and LaCl3:Ce detectors over NaI(Tl) and CZT has been discussed. The intrinsic activity of LaBr3:Ce is also demonstrated in this study.