Hemophagocytic lymphocytohistiocytosis (HLH) is a rare, life-threatening syndrome characterized by hyperactivation of cytotoxic T lymphocytes, natural killer (NK) cells, and macrophages in bone marrow (BM) and other parts of the reticuloendothelial system. This inflammatory state results in hypercytokinemia with rapidly progressive, immune-mediated injury of multiple organs. Clinically, HLH often manifests with signs/symptoms consisting of fever, splenomegaly, cytopenias, hepatitis and/or hepatomegaly, central nervous system disturbances, coagulopathy, hypertriglyceridemia, hyperferritinemia, hemophagocytosis, and diminished NK cell activity.  EBV infection may trigger HLH in individuals with defects in perforin-dependent cytotoxicity or X-linked lymphoproliferative disease (XLP), as well as in individuals without a known genetic predisposition. Remarkably, the development of HLH triggered after allogeneic and autologous stem cell transplant (SCT- HLH) has also been reported in rare cases in literature. However, this entity is very difficult to diagnose and can complicate the course of SCT, causing graft failure and high mortality. Here we report a case of patient with aplastic anemia who developed HLH following allogeneic stem cell transplant in the setting of EBV infection.