Introduction: The concept of frailty has been investigated in recent years. Currently, frailty in the elderly is understood as the presence of vulnerability to the occurrence of health-related adverse events. It was originally conceived as a construct dependent on the patient’s physical parameters. However, it is currently conceived on the basis of several physical, cognitive, emotional and social influences. Justification: Currently we do not count with enough tools in Spanish to assess frailty in the elderly, especially integrating multimodal assessments. Objectives: To develop the Multidimensional Frailty Scale (EMFRA), to cross-culturally adapt the 5-item FRAIL scale, and to explore the validity and reliability of both scales. Methods: The construction of the EMFRA will begin with a review and synthesis of the literature. Relevant factors will be identified for inclusion in the scale. A translation of the 5-item FRAIL scale will be performed. Content validation of both scales will begin with an expert panel, followed by cognitive interviews with healthcare workers and older adults. Convergent validity with physical performance will be analysed in the Short Physical Performance Battery, global cognitive function, with anxiety and depression levels, level of dependence. The criterion validity of the scales will be explored cross-sectionally with the level of dependence. The time to complete both scales, the floor effect and the ceiling effect will be analysed. The internal consistency, test-retest reliability, standard error of measurement and minimum detectable change of both scales will be studied. Keywords: Frailty; Instrument development; Validity; Content validity; Convergent validity; Criterion validity; Floor effect; Ceiling effect; Reliability; Internal consistency; Test-retest; Standard error of measurement; Minimum detectable change; Diagnosis; Older adults; Aging.