To date, little is known about enduring clinical distress as measured with the commonly used distress thermometer. We therefore used the distress thermometer to examine: (a) the prevalence of enduring clinical distress, distress-related problems, and subsequent wish for referral of women with breast cancer, and (b) sociodemographic, clinical, and psychosocial predictors of enduring clinical distress. The study had a multicenter, prospective, observational design. Patients with primary breast cancer completed a questionnaire at 6 and 15 months postdiagnosis. Medical data were retrieved from chart reviews. Enduring clinical distress was defined as heightened distress levels over time. The prevalence of enduring clinical distress, problems, and wish for referral was examined with descriptive analyses. Associations between predictors and enduring clinical distress were examined with multivariate analyses. One hundred sixty-four of 746 patients (22 %) reported having enduring clinical distress at 6 and 15 months postdiagnosis. Of these, 10 % wanted to be referred for care. Fatigue was the most frequently reported problem by patients with and without clinical distress, at both time points. Lack of muscle strength (OR = 1.82, 95 % CI 1.12-2.98), experience of a low level of life satisfaction (OR = 0.77, 95 % CI 0.67-0.89), more frequent cancer worry (OR = 1.40, 95 % CI 1.05-1.89), and neuroticism (OR = 1.09, 95 % CI 1.00-1.18) were predictors of enduring clinical distress. In conclusion, one in five women with breast cancer develops enduring clinical distress. Oncologists, nurse practitioners, and cancer nurses are advised to use single-item questions about distress and distress-related problems to ensure timely detection of high-risk patients. Providers should also routinely assess fatigue and its causes, as fatigue is the most frequently reported distress-related problem over time.