The incidence of bacteremia following hemopoietic SCT (HSCT) changes over time from the procedure. The first 30 days have the highest incidence, both in autologous and allogeneic HSCT recipients. In the following periods, bacteremia is a frequent complication in allogeneic HSCT, especially from alternative donors. Gram-positive cocci represent the most frequent cause of single-agent bacteremia. Knowledge of epidemiology (incidence and etiology) of bacteremias following HSCT is pivotal for planning management strategies (prevention, diagnosis and therapy) that must be distinct in the different post-transplant period.