It is yet undetermined whether patients with different hematological malignancies have different propensities to infectious complications after high-dose chemotherapy (HDC) and autologous hematopoietic stem cell transplantation (HSCT). We retrospectively analyzed 136 cycles of HDC and autologous HSCT in 114 patients with acute myeloid leukemia (AML, 24 cycles), non-Hodgkin's lymphoma/Hodgkin's disease (NHL/HD, 55 cycles), and multiple myeloma (MM, 57 cycles) with respect to early infectious complications. Median duration of neutropenia was longer in patients with AML and NHL/HD than in patients with MM (11 days vs 8 days) and after conditioning including total body irradiation (TBI) compared with chemotherapy only preparative regimens (11 days vs 7 days). Fever requiring antimicrobial therapy was observed in 88 percent of cycles, with fever of unknown origin (FUO) accounting for 60 percent of febrile episodes. There was no proven fungal infection, but one case of probable invasive pulmonary aspergillosis. Microbiologically documented infections were seen in 29 percent and clinically documented infections in 11 percent. Response to first-line empirical antibiotic therapy was better for FUO than for documented infections (70 percent vs 40 percent). Patients with TBI as part of their conditioning regimen had more overall infections than patients without TBI (96 percent vs 82 percent). There were no differences with respect to the type or incidence of infections between patients with AML, NHL/HD, and MM. Patients with different hematological malignancies have similar rates of early infectious complications after HDC and autologous HSCT. TBI may be associated with an increased risk for infections in the early post-transplant period.