BACKGROUND: The mobile device diffusion has increasingly highlighted the opportunity to collect patient-reported outcomes (PROs) through electronic patient-reported outcomes measurements (ePROMs) during the clinical routine. Despite the ePROMs promises and advantages, the equivalence when a PRO measure is moved from the original paper-and-pencil to the electronic version is still little investigated. This study aims at evaluating equivalence between PROMs and ePROMs self-administration in people with multiple sclerosis (PwMS); in addition, preference of self-administration type was evaluated. METHODS: The Manual Ability Measure-36 (MAM-36) and Fatigue Severity Scale (FSS) were selected for the equivalence test. The app ABOUTCOME was developed through a user-centered design approach to administer the questionnaires on tablet. Both paper-and-pencil and electronic versions were randomly self-administered. Intrarater reliability between both versions was evaluated through the intraclass correlation coefficient (ICC, excellent for values ≥ 0.75). RESULTS: Fifty PwMS (35 females) participated to the study (mean age: 54.7±11.0 years, disease course: 27 relapsing-remitting and 23 progressive; mean EDSS: 4.7±1.9; mean disease duration: 13.3±9.5 years). No statistically significant differences were found for the means total scores of MAM-36 (p = 0.61) and FSS (p = 0.78). The ICC value for MAM-36 and FSS was excellent (0.98 and 0.94, respectively). Most of participants preferred the tablet version (84%). CONCLUSION: The results of the study provide evidence about the equivalence between the paper-and-pencil and electronic versions of PROs administration. In addition, PwMS prefer electronic methods rather than paper because the information can be provided more efficiently and accurately. The results could be easily extended to other MS PROs.