The addition of bevacizumab to weekly paclitaxel as primary chemotherapy for HER-2 negative metastatic breast cancer (MBC) prolongs progression-free survival without a substantial increase of toxicity. A Markov cohort simulation was used to follow the clinical course of typical patients with MBC. Information on response rates and major adverse effects was derived, and transition probabilities were estimated, based on the results of the E2100 clinical trial. Direct costs were assessed from the perspective of the Swiss health system. The addition of bevacizumab to weekly paclitaxel is estimated to cost an additional 40,369euro and to yield a gain of 0.22 quality-adjusted life years (QALYs), resulting in an incremental cost-effectiveness ratio of 189,427euro/QALY gained. Probabilistic sensitivity analysis showed that the willingness-to-pay threshold of 60,000euro was never reached. The addition of bevacizumab to paclitaxel in MBC patients is expensive given the clinical benefit in terms of QALYs gained.