Thrombocytopenia (TP) is a frequent complication after allogeneic stem cell transplantation (SCT) and regarded as a poor prognostic factor when assessed beyond day 100. However, little is known about the clinical significance of the platelet recovery pattern before chronic graft-versus-host disease (GVHD) develops. Eighty-five patients undergoing HLA-identical sibling SCT were stratified according to their platelet recovery pattern between day +30 and +90 and the transplant outcomes analyzed, along with the association of each component of the acute GVHD grading system. Fifteen patients (18%) were classified with persistent TP, 33 patients (39%) with unstable TP, and 37 patients (43%) as non-TP. Persistent TP, which was strongly associated with severe acute GVHD (P<0.001), exhibited the worst 2-year OS (P<0.0001) and highest NRM (P<0.0001) and opportunistic infection rates (P<0.0001). In multivariate analyses, the platelet recovery pattern was identified as an independent prognostic factor (P=0.02) together with the disease risk (P=0.02) in terms of OS, and the only independent prognostic factor in terms of NRM (P=0.005) and the incidence of infectious events (P<0.001). Persistent TP was strongly associated with the development of extensive chronic GVHD (P=0.03). The platelet recovery pattern between day +30 and +90 can be used to predict the prognosis of SCT recipients.