Mixed phenotype acute leukemia (MPAL) is a relatively rare and heterogeneous group of diseases, which account for 2-5% of leukemia. So far, no optimal treatment regimens have been established for MPAL patients. CD19 chimeric antigen receptor T (CAR T) therapy have shown remarkable efficacy in B-ALL patients. In this study, 5 MPAL patients received CD19 CAR T cell infusion and 3 out of 5 patients (60%) achieved complete response (CR). 2 of 5 patients had only mild cytokine release syndrome (CRS). Neurotoxicity was not observed. Our data indicate that CD19 CAR T therapy is safe and effective for majority refractory/relapsed (r/r) MPAL patients.