BACKGROUND Old adults admitted to the hospital are at severe risk of functional loss during hospitalization. Early in-hospital physical rehabilitation programs appear to prevent functional loss in geriatric patients. The first aim of this review was to investigate the effect of early physical rehabilitation programs on physical functioning among geriatric patients acutely admitted to the hospital. The second aim was to evaluate the feasibility of early physical rehabilitation programs. METHODS Two searches, one for physical functioning and one for feasibility, were conducted in PubMed, CINAHL, and EMBASE. Additional studies were identified through reference and citation tracking. To be included articles had to report on in-hospital early physical rehabilitation of patients aged 65 years and older with an outcome measure of physical functioning. Studies were excluded when the treatment was performed on specialized units other than geriatric units. Randomized controlled trials were included to examine the effect of early physical rehabilitation on physical functioning, length of stay and discharge destination. To investigate feasibility also non randomized controlled trials were added. RESULTS Fifteen articles, reporting on 13 studies, described the effect on physical functioning. The early physical rehabilitation programs were classified in multidisciplinary programs with an exercise component and usual care with an exercise component. Multidisciplinary programs focussed more on facilitating discharge home and independent ADL, whereas exercise programs aimed at improving functional outcomes. At time of discharge patients who had participated in a multidisciplinary program or exercise program improved more on physical functional tests and were less likely to be discharged to a nursing home compared to patients receiving only usual care. In addition, multidisciplinary programs reduced the length of hospital stay significantly. Follow-up interventions improved physical functioning after discharge. The feasibility search yielded four articles. The feasibility results showed that early physical rehabilitation for acutely hospitalized old adults was safe. Adherence rates differed between studies and the recruitment of patients was sometimes challenging. CONCLUSIONS Early physical rehabilitation care for acutely hospitalized old adults leads to functional benefits and can be safely executed. Further research is needed to specifically quantify the physical component in early physical rehabilitation programs.