Background: Patient participation in decisions related to their treatment is strongly recommended. This study was conducted to develop and evaluate a support tool that can help patients make decisions related to their own treatment. Methods: Twenty cancer patients who were hospitalized for first-line treatment were enrolled. Before hospitalization, a 'Check sheet on treatment selection', which contained 14 questions, was distributed to patients and/or their families. After hospitalization, the attending physician explained the treatment while referring to the written check sheet. At discharge, patients' responses to the 'Questionnaire on check sheet and treatment selection' were collected to evaluate the utility of the check sheet. Finally, the 'Questionnaire of the check sheet' was handed to the attending physician to evaluate. Results: Of the fourteen patients who responded to the questionnaire, all indicated that the check sheets were helpful for decision-making and that using the sheets empowered them to ask their doctors questions. Only one person felt uncomfortable with compiling the check sheet. Physicians stated that the check sheet facilitated patient decision-making and improved communication with patients. However, some felt that this activity increased the administrative burden of medical professionals. Conclusion: Almost all patients stated that the present check sheet was useful as a decision support tool and facilitated communication between doctors and patients. Before incorporation into general clinical practice, this increased benefit should be weighed against the potential extra administrative workload imposed on clinicians.