Background and Objectives: In 2017, our French 1671-bed university hospital opened a 12-bed unit for very short stays, post-emergency (unit of transitory admission in geriatric [UTAG] area), dedicated to frail patients older than 75 years requiring short-term care. We sought to investigate whether this new organization's shortened length of stay (LOS) was associated or not with a higher rate of readmission. Methods: We conducted a retrospective descriptive study based on the daily activity of the UTAG over 6 months including all patients consecutively hospitalized in the unit via the computerized medical file of the hospital. The data collected included the Rockwood score, the primary diagnoses, the LOS and any 1-month readmission. Results: From August 2019 to January 2020, 646 older adult patients were hospitalized in the UTAG. Two-thirds of the hospitalized patients were women; the mean age of this population was 86.7 ± 6.2 years. The main causes of hospitalization were infectious pathologies (19.8%), falls and their consequences (17.3%), and cardiac pathologies (17.2%). The mean LOS was of 2.7 ± 2.0. Seventy readmissions were observed in the month after discharge. One-month readmissions were more frequent when patients had presented with acute heart failure and among nursing home residents. Conclusion: The creation of the UTAG reduced LOS and so contributed to decreased iatrogenic disabilities without putting patients at increased risk of readmission. The development of cardiac and geriatric dedicated outpatient pathways and a community-based geriatric mobile team intervening in nursing homes could optimize the care of frail older adult patients and avoid readmissions.