Diagnosis of secondary progressive multiple sclerosis (SPMS) is based on a history of gradual worsening of neurological symptoms within 6—12 months without exacerbations following an initial relapsing-remitting (RRMS) disease course. In the absence of reliable MRI, immunological and clinical markers, it is hardly possible to achieve objectivity in determining the transition of MS to a progressive stage. This often leads to a long period of diagnostic uncertainty, which prevents timely therapeutic decisions. Physicians expressed an unmet need for a tool that could be used in routine clinical practice to assess the risks of progression to SPMS quickly and reliably, in an easy-to-interpret output for a joint discussion with the patient. From a wide range of disease symptoms and lifestyle factors reflecting the progression to SPMS and obtained by analysis of large clinical data (3294 cases) and a survey of patients and specialists, significant were identified and ranked by categories according to combined expert opinion. A mathematical model was developed and validated, and an electronic version of the MSProDiscuss questionnaire created. Test sensitivity for SPMS diagnosis is 0.82, specificity 0.84, interrater reliability 0.95. Median time for completion of the questionnaire was 2.16 minutes per patient. Physicians of the Russian Federation who used the questionnaire confirmed its high feasibility. Thus, the methodology of the questionnaire development based on the combined opinion of patients and physicians, along with the large clinical data, made it possible to obtain high sensitivity, specificity and reproducibility of the test and takes little time with a clear output. MSProDiscuss may be useful not only in the differential diagnosis of RRMS and SPMS, but also to determine the risks of progression to SPMS, which is of great clinical importance.