Ethnicity has a major impact on the prevalence of chronic lymphocytic leukaemia (CLL) and may also influence disease phenotype. We compared the clinical features of Southern Asian and White CLL patients managed within one UK region. Asians required treatment almost twice as often as Whites (HR, 1.94) and had a shorter time to first treatment (P = 0.0063). This difference remained significant after adjusting for stage, lymphocyte doubling time and IGHV status (P = 0.026). CLL was diagnosed at younger ages in Asians and racial-specific variations in IGHV usage were demonstrated. Our findings indicate that Southern Asian race has a negative impact on CLL phenotype.