Background Effective communication between intensive care unit patients and their families and nurses promotes relationship-centered care and improves nurses’ ability to meet patient and family needs. However, communication with these patients is challenging because of their critical illness. Families often become surrogate decision makers for adult intensive care unit patients. Objective To systematically assess available evidence on communication between adult intensive care unit patients and their families and nurses as the initial step in developing nursing strategies to strengthen communication skills. Methods In this integrative review, the method of Whittemore and Knafl was used to synthesize findings from qualitative and quantitative (descriptive and experimental) research. Results The review revealed a variety of research designs, measurement tools, and types of interventions. The qualitative findings suggest that nurses can strengthen relationship-centered care by regularly updating patients’ families and providing information that can assist with decision-making. The quantitative findings suggest that nurses should be mindful of family members’ needs for assurance, comfort, and support. Providing information on patient status can help alleviate family concerns. Conclusions Improved communication between patients and families and intensive care unit nurses is essential to strengthen relationship-centered care. Additional research is needed to better understand the communication needs of adult patients and their families in the intensive care unit.