Persistent minimal residual disease (MRD) after consolidation may indicate chemotherapy insensitivity in B-precursor acute lymphoblastic leukemia (BP-ALL). Given the strong association of MRD and outcome in non-Down syndrome (non-DS) BP-ALL, it is likely that MRD levels are also of prognostic significance in DS BP-ALL. We report here the successful use of blinatumomab, a bispecific T-cell engager antibody construct, in a patient with DS BP-ALL and persistent MRD at the end of consolidation. Blinatumomab has been shown to have excellent results in patients with relapsed/refractory BP-ALL. This patient had no significant toxicity and achieved MRD negativity after only one cycle of blinatumomab.