OBJECTIVES: The Rivermead Mobility Index (RMI) is widely used in several neurological conditions including multiple sclerosis (MS), but its psychometric properties have not been documented in Scandinavia. Therefore, the aim of the study was to translate RMI from UK English into Danish and conduct an initial psychometric testing of the Danish RMI. MATERIALS AND METHODS: The Danish translation conducted by the forward-backward method was first field-tested regarding user-friendliness and relevance. It was then psychometrically tested among 40 outpatients with MS regarding unidimensionality (corrected item-total correlations, adherence to an assumed Guttman response pattern), reliability, and construct validity. RESULTS: Field testing found the Danish RMI relevant and user-friendly. Corrected item-total correlations were ≥0.47 and item responses fitted the Guttman pattern. There was a 47.5% ceiling effect, and reliability was 0.91. Correlations supported construct validity. CONCLUSION: The Danish RMI is user-friendly, unidimensional, reliable, and valid. The results correspond to those previously reported with the original UK RMI version. Ceiling effects are limiting but sample related. Larger samples representing a wider variety of MS severities are needed for firmer evaluation of the Danish RMI.