Mantle cell lymphoma (MCL) is a disease entity recently introduced into the new lymphoma classification, therefore, the clinical features as well as therapeutic outcomes in Thai patients with MCL has never been described The authors herein retrospectively analysed 21 newly diagnosed patients with MCL at King Chulalongkorn Memorial Hospital from January 1997 to December 2002. The median age of the patients was 54 years (range, 38-79). Male:female was 4:1. Generalized lymphadenopathy (67%) was the most common presenting feature. The majority of patients (85%) had advanced disease (stage III, IV, Ann Arbor system). Fifty-six percent of the patients were classified as the high- and high-intermediate risk group by the international prognostic index. Most patients were treated with CHOP (vincristine, cyclophosphamide, doxorubicin, prednisolone) or CVP (vincristine, cyclophosphamide, prednisolone) regimen. The overall complete remission rate was 59%. With a median follow-up of 13 months (range, 1-62 months), the rates of overall, progression-free and disease-free survivals were 32%, 9% and 20%, respectively. Sixty-seven percent of the patients had relapse/progressive disease after follow-up. In conclusion, the clinical features as well as the outcomes of Thai patients with MCL were comparable to patients in Western countries. Newly diagnosed patients should be treated with novel modalities other than conventional CHOP chemotherapy in order to improve the outcomes.