Transplant-associated thrombotic microangiopathy (TA-TMA) is a serious complication of hematopoietic stem cell transplant (HSCT). This study reviews pediatric allogeneic HSCTs at Oregon Health and Science University (OHSU) from August 2008 to September 2019, focusing on the incidence of TA-TMA and the use of eculizumab, a complement inhibitor introduced in July 2015. Modified diagnostic criteria were used to identify TA-TMA cases. Among 142 patients, 17 (12.0%) met all criteria: 6 of 85 patients (7%) were identified pre-eculizumab (2008-2015), while 11 of 57 (19%) were identified post-eculizumab (2015-2019). In the post-eculizumab era, TA-TMA patients were more likely to be admitted to the pediatric intensive care unit (82% vs. 24%, P=0.006). There was no significant impact on the diagnosis of GVHD. This experience indicates an increased incidence of TA-TMA at OHSU since 2015, particularly in non-malignant transplants.