The aim of this study was to evaluate the extent to which hospitalised patients with advanced cancer and a palliative treatment goal wanted to be involved in the process of making treatment decisions and how well their physicians actually knew their preferences for participation. 59 hospitalised patients with non-curable cancer, 86 hospitalised patients with chronic non-neoplastic disease, and 115 non-hospitalised persons were surveyed with a standardised questionnaire. In addition, the physicians of the hospitalised patients were asked to complete a similar questionnaire. The majority of patients with advanced cancer wanted to decide either by themselves/mainly by themselves (9%) or to collaborate and decide together with their physician (73%), compared with 17% and 49%, respectively, of patients with chronic non-neoplastic disease, and 40% and 56%, respectively, of the non-hospitalised persons (difference between groups: P = 0.001). Younger age, higher education, employment and higher Karnofsky index were significantly associated with active involvement. The agreement of patients' preference with their physicians' assessment did not exceed chance. In conclusion, most patients wanted to participate in a decision regarding their treatment, although physicians were unaware of their patients' preferences.