To explore the incidence and clinical characteristics of engraftment syndrome (ES) after syngeneic hematopoietic stem cell transplantation (syn-HSCT) in patients with hematological diseases. The clinical data of 21 patients who received syn-HSCT at People’s Hospital of Peking University from January 1994 to May 2018 were retrospectively analyzed. Seven (33.3% ) of 21 patients developed ES. The onset of ES symptoms occurred at a median of 8 (range: 5-13) days after HSCT, and the diagnosis of ES occurred at a median of 10 (range: 7-14) days after HSCT. Steroids were administered immediately after the diagnosis of ES, the median time of symptom continuance was 2 (range: 1-5) days, and all patients showed complete resolution of ES symptoms. In the multivariate analysis, patients with acute myeloid leukemia and faster neutrophil reconstitution were the risk factors for ES (=15.298, 95% 1.486-157.501, =0.022, and =17.459, 95% 1.776-171.687, =0.014) . Meanwhile, there was no significant difference in the overall survival and disease-free survival between patients with ES and those without ES. A high incidence of ES was observed in syn-HSCT recipients. Moreover, the prognosis of ES was excellent.