Background: Patients (pts) with adverse risk AML experience poor long term disease control. Some of these pts can be rescued with allogeneic stem cell transplantation (SCT). Adverse risk was defined by high risk cytogenetic and molecular markers (2017 European Leukemia Network criteria) and by disease status prior to SCT. We investigated outcomes of pts receiving in vivo T-cell depleted allogeneic SCT (TCD-SCT) at our center. Methods: We retrospectively analyzed 200 adverse-risk AML pts who received TCD-SCT from 2002-19. Pts were categorized into groups: untreated first relapse at SCT, primary induction failure with active disease at SCT, resistant to first induction but achieving morphologic complete remission (CR) by SCT, and induction sensitive CR with high-risk disease by ELN criteria. Outcomes were evaluated by 1-year (yr) and 3-yr relapse-free survival (RFS), overall survival (OS), and non-relapse mortality (NRM), and compared with log-rank tests of significance. Results: Baseline pt characteristics included a median age of 54 years (IQR, 44-61) with 62 (31%) pts older than 60, and 81 (41%) with HCT-CI score 3 or greater. All pts underwent in vivo TCD with alemtuzumab or ATG; 153 (77%) received reduced-intensity conditioning; 142 (71%) had 8/8 or 7/8 matched donors. Fourteen (7%) pts developed grade III-IV acute graft versus host disease (GVHD), and 25 (13%) developed chronic GVHD. With a median follow up of 14.3 months, cumulative incidence of relapse was 59% and NRM was 27%. Outcomes are summarized in the table. There was a statistically significant difference between categorized groups by RFS (p<0.01) and OS (p<0.01). Conclusions: We conclude that among adverse-risk AML pts, those in CR at time of TCD-SCT have superior survival outcomes to those with active disease. For those in CR at TCD-SCT, prior resistance to frontline induction was associated with inferior survival, suggesting that AML biology, treatment sensitivity, and remission status are important factors for TCD-SCT outcomes. The inferior outcomes observed for those with primary refractory disease suggest that while TCD-SCT can be effective with acceptable NRM, more work is needed to identify which pts can benefit from future transplant strategies. Better post-SCT therapy is needed to prevent relapses.