OBJECTIVES: This is a retrospective cohort study examining the development of prolonged neutropenia as a result of the induction chemotherapy R-CHOP/CHOP in diffuse large B-cell lymphoma (DLBCL) patients. It aims to 1) identify the incidence and predictive factors of the prolonged neutropenia, and 2) evaluate the infection complications and clinical outcomes of prolonged neutropenia in this patient group. METHODS: Medical records of 43 DLBCL patients who received R-CHOP/CHOP induction treatment between the year 2000 and 2010 at Prince of Wales Hospital (PWH) were reviewed.  Information including basic demographic information, disease-related characteristics, and laboratory values were recorded.  Incidence of prolonged neutropenia, duration of neutropenic episodes, and infection complication and outcomes were also collected. Correlations between possible predictive/risk factors and the occurance of prolonged neutropenia were examined using univariate analysis and multivariate logistic regression analysis. RESULTS: Inpatient status (OR: 12.000, p-value = 0.006), Ann Arbor stage III or IV (OR: 3.886, p-value = 0.049) and International Prognostic Index (IPI) high risk group (OR: 5.257, p-value = 0.020) were identified as predictive factors of prolonged neutropenia. Prolonged neutropenia has been shown to cause significant longer duration of hospitalization, increased ICU admission, dose reduction and delay in chemotherapy or even early termination of treatment. The use of prophylactic G-CSF and/or antibiotics has also been shown to reduce the occurrence of prolonged neutropenia. CONCLUSIONS: Several predictive factors were demonstrated to have association with the occurrence of prolonged neutropenia in DLBCL patients after receiving R-CHOP/CHOP. Preventive measures, including prophylactic G-CSF and/or antibiotics, should be considered as part of the treatment for the patients at risk.