Transitional care is a time-limited service to prevent discontinuous care and adverse outcomes, including rehospitalization. To describe transitional care interventions and evidence of benefit or harm in patients hospitalized for acute stroke or myocardial infarction (MI). Cumulative Index to Nursing and Allied Health Literature, MEDLINE, Cochrane Database of Systematic Reviews, and EMBASE, supplemented with manual searches of reference lists of relevant studies and review articles (January 2000 to March 2012). 6 reviewers screened 5857 citations to identify English-language reports of trials or observational studies that compared transitional care with usual care among adults hospitalized for stroke or MI and that reported patient, caregiver, process, or systems outcomes within 1 year of hospital discharge. Data on study design, quality, population, intervention characteristics, and patient- and system-level outcomes were extracted by 3 reviewers and confirmed by 1 additional reviewer. 62 articles representing 44 studies of transitional care for either acute stroke (27 studies) or MI (17 studies). Four intervention types were studied: hospital-initiated support (n = 14), patient and family education (n = 7), community-based support (n = 20), and chronic disease management (n = 3). Most studies (68%) were of fair quality. Overall, moderate-strength evidence showed that hospital-initiated support reduced length of stay for patients who had a stroke, and low-strength evidence showed that it reduced mortality for patients who had an MI. Evidence about benefits of other interventions and harms from transitional care services was insufficient. Few studies had high-quality research designs. The usual care comparator was often poorly defined. Applicability to U.S. clinical practice was limited; only 6 studies were conducted in the United States. Available evidence shows that hospital-initiated transitional care can improve some outcomes in adults hospitalized for stroke or MI. Finding additional transitional care interventions that improve functional outcomes and prevent rehospitalizations and adverse events is a high priority for the growing population of patients who have an MI or a stroke. Agency for Healthcare Research and Quality.