['Patients treated with radical prostatectomy (RP) or radiation therapy (RT) for prostate cancer can experience stress and symptoms that impact quality of life.', 'The objectives of this study were to describe cortisol levels, perceived stress, symptoms, and symptom distress; compare differences in variables measured between RP and RT; and identify associations among cortisol levels, perceived stress, symptoms, and symptom distress in patients treated for localized prostate cancer.', 'A descriptive, cross-sectional study was conducted with 53 patients (RP n = 24, RT n = 29). Data from saliva, questionnaires, and interviews were collected within 3 months of treatment. Saliva samples were collected at 4 times over 2 consecutive days. Data were analyzed using descriptive statistics, correlations, and regressions.', 'A robust diurnal rhythm of cortisol secretion with heightened levels in the early morning and lowered levels late in the day was found. On average, the entire sample had moderate symptoms and symptom distress for urinary, bowel, and sexual dysfunction. The RP group reported significantly more urinary and sexual dysfunction symptoms and fewer bowel symptoms than did the RT group. Perceived stress was positively correlated with higher afternoon cortisol levels and greater symptom distress.'] Is high perceived stress linked to afternoon cortisol levels and greater symptom distress in patients with localized prostate cancer?