Recent research has revealed that prostate cancer (PCa) survivors are facing a silent epidemic of mental disorder. These findings are not surprising when the side effects of highly effective current treatment modalities are considered. Here, we assess the association between urinary function and quality of life indicators to mental disorder among survivors of PCa. This is a cross sectional examination of an analytical sample of 362 men with a history of PCa residing in the Maritimes who took a survey assessing social, physical and health-related quality of life indicators between 2017 and 2021. Mental disorder was assessed using Kessler’s Psychological Distress Scale (K-10). Predictor variables included emotional, functional, social/family and spiritual well-being, measured by Functional Assessment of Cancer Therapy-Prostate (FACT-P), and urinary function was measured by International Prostate Symptom Score (IPSS). Multivariate logistic regression analysis evaluated the contribution of predictors while controlling for age, income, survivorship time (months) since diagnosis, relationship status and treatment modality. Mental disorder was identified among 15.8% of PCa survivors in this sample. High emotional (aOR = 0.81, 95% CI: 0.69–0.96) and spiritual well-being (aOR = 0.88, 95% CI: 0.81–0.96) were protective factors against mental disorder. Men who screened positive for moderate to severe urinary tract symptoms had three times higher odds (aOR = 3.02, 95% CI: 1.10, 8.32) of screening positive for mental disorder. Men who were on active surveillance or radical prostatectomy with or without added treatment had higher (aOR = 5.87, 95% CI: 1.32–26.13 or aOR = 4.21, 95% CI: 1.07–16.51, respectively) odds of screening positive for mental disorder compared to men who received radiation treatment with or without hormonal therapy for their PCa diagnosis. Unmet emotional and spiritual needs, increased urinary problems and some forms of treatment (e.g., active surveillance or surgery) were associated with mental disorder among PCa survivors. The development of survivorship care programs and support systems that focus on the long-term effects of PCa treatments and the consequences of unmet psychosocial needs of patients during the survivorship journey are critically needed.