The purpose of our study was to determine the effectiveness of 2-CdA in 2-hour intravenous infusions in the treatment of B-CLL. One hundred and ten patients with B-CLL received 1 to 10 courses of 2-CdA (median 2.5) at a dosage of 0.12 mg/kg daily for 5 consecutive days. Eighteen of them were untreated and 92 relapsed or became refractory to previous therapeutic modalities. Complete remission (CR) was achieved in 8 (7.3%) and partial remission (PR) in 35 patients (31.8%) giving an overall response rate of 39.1%. In 3 patients, cross-resistance to fludarabine was noticed. Toxic effects of 2-CdA were more frequently observed in previously treated patients. Hemorrhagic complications due to drug-induced thrombocytopenia were noticed in 25 (22.7%) and severe infections including sepsis in 14 (12.7%) patients.