Communication between families and providers in the ICU affects patient and family outcomes and use of health-care resources. Recent research studies have tested interventions designed to improve communication quality and outcomes between providers and families of patients in the ICU. We conducted a systematic review of these studies. We searched the MEDLINE, PsychInfo, Cochrane, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases from 1995 to July 2010. We included studies that reported controlled clinical interventions designed to improve communication between providers and families of patients in the ICU aged 18 years or older. We abstracted all selected studies to a standardized data collection instrument and completed a quality checklist based on recommendations from the Consolidated Standards for Reporting Trials (CONSORT) investigators. In all, 2,841 articles were identified. Of those articles, 180 met the criteria for full review, and 21 articles of 16 distinct interventions met the full inclusion criteria, of which five were randomized. Interventions studied included printed information or structured family conferences, with or without additional family support. Conferences aimed to communicate the diagnosis and prognosis, elicit patient values, assess family understanding, and clarify the goals of treatment. Printed information, palliative care or ethics consultation, or regular, structured communication by the usual ICU team reduced family distress, improved comprehension, and decreased the use of intensive treatments. The evidence supports the use of printed information and structured communication by the usual ICU team, ethics consultation, or palliative care consultation to improve family emotional outcomes and to reduce ICU length of stay and treatment intensity. Evidence that these interventions reduce total costs is inconclusive. A comprehensive research agenda should ensure the future study of a full range of patient-centered outcomes.