OBJECTIVES: To test the effects of a modified Hospital Elder Life Program (mHELP) on frailty. DESIGN: Matched and unmatched analyses of data from a before-and-after study. SETTING: Hospital, inpatient. PARTICIPANTS: Participants aged 65 and older (n = 189) undergoing major elective abdominal surgery at a medical center in Taiwan. INTERVENTION: The mHELP included three nursing interventions: early mobilization, oral and nutritional assistance, and orienting communication. MEASUREMENTS: Frailty rate and transitions between frailty states from hospital discharge to 3 months after discharge using Fried's phenotype criteria categorized as nonfrail (0 or 1 criteria present), prefrail (2 or 3 criteria present), and frail (4 or 5 criteria present). RESULTS: In matched pairs, participants who received the mHELP interventions were significantly less likely to be frail at discharge (19.2%) than matched controls (65.4%) (adjusted odds ratio (AOR) = 0.10, 95% CI = 0.02-0.39). Transitions to states of greater frailty during hospitalization were more common for participants in the control group. Three months after discharge, participants who received the mHELP intervention during hospitalization were less likely to be frail (17.3%) than matched controls (23.1%) (AOR = 0.73, 95% CI = 0.21-2.56), although this difference did not achieve statistical significance. CONCLUSION: The mHELP intervention is effective in reducing frailty by hospital discharge, but the benefit is diminished by 3 months after discharge. Thus, the mHELP provides a useful approach to manage in-hospital frailty for older adults undergoing major abdominal surgery. Geriatrics Society.