Aim Comparison between the predictions of functional rehabilitation outcomes at a department of geriatric rehabilitation using three cognitive screening tools – Mini Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). Methods This study is a prospective study. The study participants were 212 patients aged 65 and older admitted to rehabilitation departments at a geriatric facility in central Israel, from April 2016 to October 2016. The cognitive functioning of each patient was assessed using the MMSE, MoCA, and IQCODE. Upon discharge, rehabilitation outcomes were examined using the Functional Independence Measure (FIM), cognitive FIM, delta FIM (Δ FIM), and ADL. Results Cognitive impairment was found to interfere with the rehabilitation process. The MMSE was the best predictor of functional rehabilitation outcomes at discharge, compared to the IQCODE, while the MoCA did not predict these measures. In addition, when distinguishing between patients by ethnicity (Jewish versus Arab), the MMSE and the IQCODE predicted FIM upon discharge among Jewish patients, while only the IQCODE predicted FIM upon discharge among Arab patients. Conclusions The research findings show that cognitive assessment upon admission for rehabilitation – MMSE among Jewish patients and IQCODE among Arab patients – can help predict functional rehabilitation outcomes and make the appropriate adaptations in the rehabilitation program. Geriatr Gerontol Int 2017; ••: ••–••.