BACKGROUND & AIMS: Several hip fracture patients are malnourished, but no study has attempted to determine the optimal nutritional screening tool for predicting functional outcomes. We investigated the association between each nutritional status assessed by four nutritional screening tools at admission and functional outcomes during the postoperative acute phase in hip fracture patients. METHODS: The Mini Nutritional Assessment-Short Form (MNA-SF), the Malnutrition Universal Screening Tool (MUST), the Nutritional Risk Score 2002 (NRS-2002) and the Geriatric Nutritional Risk Index (GNRI) were assessed at admission before surgery. We evaluated the motor domain of the functional independence measure (motor-FIM) score at discharge, efficiency on the motor-FIM (change in the motor-FIM score after postoperative rehabilitation divided by postoperative length of hospital stay), and 10-m walking speed at postoperative 14 days as functional outcomes. RESULTS: Two hundred and five patients (mean patient age, 83.5 ± 7.0 years; range, 65-100 years; 82% female) were included. The MNA-SF evaluation classified 56 patients as well-nourished, 103 as at risk of malnutrition and 46 as malnourished. The MUST evaluation classified 97 patients as low risk, 42 as medium risk and 66 as high risk. The NRS-2002 evaluation classified 89 patients as well-nourished, 69 as medium risk and 47 as nutritionally at risk. The GNRI evaluation classified 44 patients as no risk, 74 as low risk and 87 as a major risk. Multiple linear regression analysis revealed that MNA-SF had a significant association with discharge motor-FIM (well-nourished vs. at risk of malnutrition, standardised β = -0.06, p = 0.04; vs. malnourished, standardised β = -0.32, p < 0.01), efficiency on the motor-FIM (well-nourished vs. malnourished, standardised β = -0.19, p = 0.02) and 10-m walking speed (well-nourished vs. malnourished, standardised β = -0.30, p < 0.01). The GNRI was significantly associated with 10-m walking speed (no risk vs. mild risk, standardised β = -0.23, p = 0.02; vs. major risk, standardised β = -0.37, p < 0.01), but not of motor-FIM and efficiency on the motor-FIM. No significant relationships were found among MUST and NRS-2002 and any functional outcomes. CONCLUSIONS: The MNA-SF was found to be an optimal nutritional screening tool to associate with functional outcomes during the postoperative acute phase of elderly hip fracture patients.