The purpose of this study was to investigate the participatory experience in the treatment related decision-making process of patients receiving radical prostatectomy or high-dosage brachytherapy for localized prostate cancer. Between March 2005 and May 2005, ten patients diagnosed with localized prostate cancer were recruited by purposive sampling at a medical center outpatient department and ward and included in this study, based on a qualitative study design. Semi-structured, guided interviews were employed to collect data. Data were analyzed by content analysis. Results showed that the decision-making experience of these localized prostate cancer patients included the items of greatest concern to patients as well as addressed the factors that made treatment decision-making difficult. Findings may be referenced by medical personnel when they are charged to select optimal treatment options for patients with prostate cancer.