We investigated the effects of a single s.c. injection of peg-filgrastim in 32 patients with multiple myeloma who underwent autologous stem cell transplantation (AuSCT) as first line treatment. For comparison, 32 myeloma patients with similar characteristics and receiving standard daily administration of filgrastim were matched. Overall, there were no statistically significant differences between peg-filgrastim and filgrastim in terms of tolerability, marrow recovery, severity of neutropenia, incidence and duration of febrile neutropenia, documented infections and transfusions. However, some favourable trends or effects in favour of peg-filgrastim were observed. This was confirmed by a review of the published papers about this topic.