OBJECTIVES: To investigate the impact of chronic lymphocytic leukaemia (CLL) on health-related quality of life (HRQL) and the gain in terms of descriptive richness associated with using an EQ-5D with additional levels (EQ-5D-5L) in the CLL patient population. METHODS: The EQ-5D-5L employed in this study incorporates 5 levels of assessment but without additional labelling (Levels 2 and 4 are unlabeled). Our study involves a cohort of patients with CLL from 19 participating Dutch centres. Health-related quality of life (HRQL) is assessed at 6 monthly intervals. The following analysis is based on the initial HRQL assessment, which captured patients at various phases in their disease course. RESULTS: In March 2006, 134 patients had completed at least one EQ-5D-5L questionnaire of whom 63% were male of median age 66 years. Median age for females was higher at 70 years. Most patients (72%) were in remission at the time of the first HRQL assessment. Twenty-six percent selected at least one alternative level on the EQ-5D-5L. The dimensions where patients reported most problems were Pain/Discomfort (level 1: 57%, level 2: 8%, level 3: 32%, level 4: 1%) and Usual Activities (level 1: 62%, level 2: 7%, level 3: 28%, level 4: 2%, level 5: 1%), followed by the Mobility dimension (level 1: 69%, level 2: 8%, level 3: 22%). Few patients reported problems in terms of Self-care (5%). The mean VAS score was 75.08 (SD=14.3). Utility scores were 0.88 (SD=0.15) for the EQ-5D-5L, slightly higher than for the 3-level categorization at 0.84 (SD=0.15). CONCLUSION: Results obtained thus far suggest that the HRQL of CLL patients in remission is high. Patients utilize the additional categories provided with a 5-level instrument. However, in this case the labelled levels still attracted the greatest percentage of answers, which may be a function of the design of the questionnaire.