We performed a retrospective study of the engraftment syndrome (ES) as defined by the Spitzer Criteria in adult patients undergoing allogeneic hematopoietic cell transplantation (HCT) for various hematological malignancies at a single institution, over a decade, and analyzed its relationship to acute GVHD; 217 patients underwent either myeloablative (38.7%) or reduced intensity (61.3%) HCT; 22.1% met the criteria for ES. Acute GVHD prophylaxis (P=0.006) and transplants prior to 2006 (P<0.0001) were significantly associated with a risk of ES in univariable analysis. Early aGVHD within 4 weeks of engraftment was significantly more common in the ES compared to the non ES cohort (21 vs. 8.3% respectively, P=0.02). ES did not predict for future GVHD, as at day +180, the cumulative incidences of grades II-IV aGVHD (31 vs. 23%, P=0.19) and of chronic GVHD at 2 years of engraftment (42 vs. 36%, P=0.28) were not significantly different between the ES and non ES groups, respectively. No significant differences in NRM, overall survival and progression-free survival were observed between the two groups. Although predictive of early aGVHD, ES occurred independently of GVHD in 79% of the patients. Survival outcomes should be evaluated in a larger randomized study to investigate if there is a correlation with ES. Am. J. Hematol. 89:698-705, 2014.