Background: Minimal residual disease (MRD) assessment can identify patients with ALL at increased risk for relapse and death. However, the impact of achieving CMR in Ph+ ALL remains undefined. Methods: Between 4/2001 and 12/2015, 202 adult patients with Ph+ ALL received frontline chemotherapy plus a tyrosine kinase inhibitor at our institution. Of these, 196 achieved CR and 122 had MRD assessments for BCR-ABL1 by RQ-PCR both at CR and at 3-month time points; 37 patients underwent stem cell transplant (SCT) and were excluded, leaving 85 patients evaluable for this analysis. Patients received hyperCVAD plus imatinib (n = 23), dasatinib (n = 39) or ponatinib (n = 23). Major molecular response (MMR) was defined as a BCR-ABL1/ABL1 ratio < 0.1% standardized to the international scale, and CMR was defined as the absence of a quantifiable BCR-ABL1 transcript. Results: Median duration of survivor follow-up was 30 months. Molecular response rates at CR and at 3 months and their respective 3-year OS and RFS rates are summarized in the Table. Overall, MRD status at 3 months had better discrimination for OS and RFS than did MRD status at CR. At CR, no difference in OS or RFS was observed between patients achieving CMR and those with lesser responses (P = 0.26 and P = 0.15, respectively). At 3 months, achievement of CMR was associated with longer median OS and RFS compared to those with lesser responses (127 vs. 38 months, P = 0.009; and 126 vs. 18 months, P = 0.007, respectively). Patients with CMR at 3 months also had superior OS and RFS compared to those who achieved MMR at the same time point (P = 0.04 and P = 0.05, respectively). Among the 51 patients who achieved CMR at 3 months, there was no impact of molecular response at CR on either OS or RFS (P = 0.79 and 0.48, respectively). Conclusions: Patients with Ph+ ALL who achieve CMR at 3 months have superior outcomes compared to those with lesser molecular responses.