Aim To explore medical decision making in octogenarians having cardiac surgery. Methods Five focus groups conducted in a private hospital setting with octogenarians of high socioeconomic status who had successful cardiac surgery in the previous 3–13 months. Results Octogenarians motivations for having cardiac surgery include survival, relief of symptoms, convenience and improving quality of life. The decision to have surgery involved clinical advice by doctors that the time had come to take up a surgical option. Patient's decisions did not take into account alternative treatment options either because these had not been presented by doctors or because medical management had failed. The final decision was made by patients. Conclusions Decisions to have cardiac surgery in octogenarians are made by patients after discussions with family based on their risks as communicated by their doctors. This underlines the importance of effective risk communication by doctors to help patients make appropriate medical decisions.