[en] The objective was to assess the quality of life (QoL) of patients with localized prostate cancer (LPC) after treatment by radical radiotherapy (RR). An ''ad hoc'' self-administered questionnaire was developed, which comprised a series of 41 items grouped into seven subscales reflecting the main QoL domains, and the questionnaire's psychometric properties were assessed. Ninety patients (76%) completed the questionnaire; because 20 of them were also treated with hormonal therapy, QoL was assessed only in the remaining 70 patients, to avoid confusion. The assessment of the psychometric properties showed that the questionnaire was valid and reliable (Cronbach's α coefficient >0.8 for each subscale). The main side effects of RR were urinary symptoms and sexual impairment, while physical, psychological and relational well-being were good. The degree of information available about the therapy and the disease seemed to play a major role in the patients' QoL adjustment after RR. (Author)