Pegfilgrastim (Neulasta) has proven efficacy as supportive therapy in a variety of 21-day chemotherapy regimens, but has not been studied in dose intensive, rapidly cycling regimens utilising cell-cycle active drugs (e.g. anti-metabolites) such as hyper-CVAD. This study examined whether pegfilgrastim was safe and lead to similar kinetics of neutrophil recovery as daily granulocyte colony stimulating factor (G-CSF). Using retrospective analysis, patients receiving pegfilgrastim (6 mg) were matched with controls (G-CSF 5 microg kg-1 per day) for a cycle of chemotherapy, prior chemotherapy, dose of cytarabine received, age (<60 or >60 years), diagnosis and bone marrow involvement. The primary endpoint was duration of grade IV neutropenia (absolute neutrophil count, ANC < 500 microl-1). Secondary endpoints included time to neutrophil recovery, incidence of febrile neutropenia, positive blood cultures and delay in subsequent chemotherapy. This study identified 124 pegfilgrastim supported cycles in 43 patients and successfully matched them to 124 G-CSF supported cycles from 38 patients treated between January 1999 and July 2005. There were no significant differences between pegfilgrastim and G-CSF groups in baseline or treatment-related variables. The median duration of grade IV neutropenia was 4 days in both groups (P = 0.55). Time to neutrophil recovery, incidence of febrile neutropenia, positive blood cultures and delay in subsequent chemotherapy were similar in both groups. Once per cycle dosing of pegfilgrastim appears safe and as effective as daily G-CSF for supporting the hyper-CVAD chemotherapy regimen.