Background: The prognosis of T-cell lymphoma is poor. To explore the addition of the monoclonal antibody alemtuzumab, we studied the efficacy and tolerability of an intensified alemtuzumab-chemotherapy combination for aggressive T-cell lymphoma in a phase II study by Dutch-Belgian Hemato-Oncology Group (HOVON). Patients and methods: Patients (< 65 years) with newly diagnosed T-cell lymphoma received eight CHOP cycles (cyclophosphamide, doxorubicin, vincristine, prednisone) 2-weekly, each cycle with three doses of 30 mg alemtuzumab. Prophylaxis consisted of cotrimoxazole, fluconazole and valaciclovir. Cytomegalovirus (CMV) monitoring took place at least every fortnight. Results: Twenty patients from 10 centers, median age 50 years, were included. Eighty-five percent received six or more cycles. The overall response was 90% [12 complete remissions (CRs), 1 CR unconfirmed, 5 partial remissions]. Median duration of follow-up of patients still alive was 29 months (range 19-41 months). Median overall survival (OS) and event-free survival (EFS) were 27 and 10 months, with 55%/27% OS/EFS at 2 years. Adverse events consisted of neutropenic fever (n = 8) and CMV reactivation (n = 7), with one CMV disease. Three patients developed secondary Epstein-Barr virus (EBV)-related lymphoma, all after end of treatment. Conclusions: Although intensified alemtuzumab-CHOP induces high responses, many patients relapse, and the scheme is associated with serious infection-related adverse events. EBV monitoring after end of treatment is required.