OBJECTIVE: Older adults are at risk of rehospitalization if their care transitions from hospital-to-home are not properly managed. The objective of this review was to determine if older patient populations recruited for randomized controlled trials of transitional care interventions represented those at greatest risk of rehospitalization following discharge. Relevant risk factors examined were cognitive impairment, depression, polypharmacy, comorbidity, length of stay, advanced non-malignant diseases, and available social support. DESIGN: Systematic review. SETTING: Hospital to home. PARTICIPANTS: Older hospitalized adults. MEASUREMENTS: For inclusion, articles were required to focus on hospital-to-home transitions with a self-care component, have components occurring both before and after discharge, and a randomized controlled trial design. Articles were excluded if participants had a mean age under 55 years, or if interventions focused on developmental disabilities, youth, addictions, or case management, or were solely primary-care based. RESULTS: Following title, abstract, and full review by two authors, 17 articles met inclusion criteria. Risk factors for rehospitalization were often listed either as exclusion criteria or were not reported at baseline by the studies. One study included patients with all identified risk factors for rehospitalization. CONCLUSIONS: These data suggest that published studies of transitional care interventions do not often include older adults at highest risk of rehospitalization, raising concerns about the generalizability of their results. Studies are needed that evaluate interventions that explicitly address the needs and characteristics of these patients.