OBJECTIVES Myxomatous mitral valve disease (MMVD) presents a frequent heart problem in dogs. The objective of this study was to estimate the cost-effectiveness of pimobendan compared to benazepril for treatment of MMVD in dogs in Switzerland. METHODS A Markov model including the health states asymptomatic MMVD, symptomatic MMVD, treatment failure, euthanasia, and sudden death, was adapted to Switzerland. Costs (year 2008, perspective of the dog owner) and benefits (life days gained, time without symptoms of heart failure) were calculated over a 1-year time horizon for dogs on pimobendan or benazepril respectively, both on concurrent furosemide treatment. Most transition probabilities were based on randomized controlled trials. Missing data and input-data on treatment pattern were obtained from experts in canine cardiology. RESULTS Mean survival over the 1-year time horizon was 274 days for dogs on pimobendan versus 129 days for dogs on benazepril. Time spent without any symptoms of heart failure was 86 days for pimobendan versus 15 days for benazepril. Mean total therapy cost per dog on pimobendan was CHF 905.68 versus CHF 546.52 for benazepril; resulting in a cost of CHF 2.48 for each additional day of life on pimobendan. Mean costs per treatment day were lower with pimobendan (CHF 3.31) compared to benazepril (CHF 4.24). Extensive one-way and probabilistic sensitivity analyses confirmed the robustness of the results. CONCLUSIONS Pimobendan is a cost-effective treatment of MMVD if the dog owner is willing to pay a price within the normal range of food costs for each additional day of life. The results indicate a better quality of life of dogs on pimobendan, as they spent substantially more time without any symptoms of heart failure compared to dogs on benazepril. Lower total treatment costs for benazepril are merely attributed to a shorter survival, as pimobendan resulted in less costs per treatment day.