Prior studies have suggested that lower blood pressure increases the mortality risk in the elderly. This study examines the relationship between change in blood pressure and overall mortality in frail elderly patients. Medline, PubMed, Cochrane, and Google Scholar databases were searched until April 2, 2015 using search terms: frail/frailty, elderly/aged, blood pressure, hypertension, cardiovascular events, and mortality/prognosis. Two-arm prospective and retrospective studies that investigated BP and the incidence of mortality in frail elderly patients were included. We found that the chance of mortality decreased with increasing systolic blood pressure (SBP) (pooled HR = 0.870, 95% CI = 0.776–0.976, P = 0.018) and diastolic blood pressure (DBP) (pooled HR = 0.837, 95% CI = 0.77–0.911, P < 0.001). Pulse pressure was not associated with mortality risk (pooled HR = 0.949, 95% CI = 0.897–1.004, P < 0.071). In elderly frailty patients, hypertension has a protective effect in lowering risk of overall mortality. Accurate identification of such elderly population is necessary for optimizing health care.