Research has validated the desire of patients and families for ongoing prognostic information; however, few conversations occur before patients reach the advanced stages of their disease trajectory. Physician hesitance and delay in discussing unfavorable prognoses deny patients and families optimal time to prepare for critical decision making. Advanced practice registered nurses can play a crucial, complementary role with the critical care interdisciplinary team to implement strategies to improve communication about prognosis and end of life with patients and families. Clinicians should discuss deterioration in disease-specific characteristics and changes (decline) in functional status. Functional status can serve as an accurate guide for forecasting prognosis, particularly in patients with heart failure, stroke, chronic lung disease, and end-stage renal disease. This article provides an overview of effective intensive care unit prognostic systems and discusses barriers and opportunities for nurses to use evidence-based knowledge related to disease trajectory and prognosis to improve communication and the quality of palliative and end-of-life care for patients.