OBJECTIVES: To compare, from a Dutch health care payer perspective, bendamustine against chlorambucil. The latter is the current first line treatment for CLL patients with Binet stage B or C for whom fludarabine combination therapy is not appropriate. METHODS: A Markov model to reflect the treatment sequence of patients with CLL in the Netherlands was developed in Treeage pro suite 2009 linked to Excel 2007. Three treatment lines were modelled before patients reached best supportive care. This treatment path was supported by a Dutch CLL expert panel. Transition probabilities were derived from clinical trials, the expert panel and Dutch mortality statistics. Healthcare resource utilisation was estimated for each health state using clinical guidelines and the expert panel. Model outcomes were life years (LY), quality-adjusted life years (QALYs), progression free life years (PFLY), and total CLL related health care costs (2011 values). The model time horizon was 10 years and monthly cycles were used. Annual discounting of 4%/1,5% was applied on costs and effects, respectively. RESULTS: The analysis showed that patients with bendamustine and chlorambucil as first line treatment generated 3.77 and 2.21 QALYs, respectively. The total average costs amounted to €79,328 for bendamustine, and €67,172 for chlorambucil. The incremental cost effectiveness ratio (ICER) of bendamustine compared to chlorambucil was €7,809 per QALY gained. The incremental cost per LY and PFLY gained were €7,374 and €6,908. The cost-effectiveness acceptability curve indicated that the probability that bendamustine was cost-effective approximated 95% at a threshold of €20,000 per QALY. CONCLUSIONS: Bendamustine compared to chlorambucil, in previously untreated Binet B or C CLL patients for whom fludarabine combination therapy is not appropriate, generated an ICER of €7,809 per QALY gained. This indicated that bendamustine is cost-effective as first line treatment for CLL in the Netherlands.