Prostate cancer is the most common malignancy in older men. With the aging of the population, the number of older men with prostate cancer will grow rapidly. Androgen deprivation therapy (ADT) is the mainstay of treatment for men with systemic disease and is increasingly utilized as primary therapy or in combination with other therapies for localized disease. Side effects of therapy are multifold and include hot flashes, osteoporosis, and adverse psychological and metabolic effects. Recent research has illustrated that ADT can negatively impact the functional, cognitive, and physical performance of older men. Patients with prostate cancer, despite recurrence of the disease, have a long life expectancy and may be subjected to the side effects of ADT for many years. This review highlights the complications of ADT and approaches to management. We also provide recommendations for assessment and management of ADT complications among the most vulnerable and frail older male patients.