With the development of new immunomodulating therapies, with which early use is strongly encouraged, it is crucial to be in possession of reliable clinical predictors of multiple sclerosis evolution. Prognostic factors are important to patients wanting to be informed about their prospects; to the clinician needing to individualize patients requiring immune treatments at an early stage of the disease; and also to the researcher needing to to improve the design and analysis of the clinical therapeutic trials and observational studies. Frequentist analyses have indicated a poor prognosis for male gender, late age at onset, motor, cerebellar and sphincter involvement at onset, progressive course at onset, short inter-attack interval, high number of early attacks; and a relevant early residual disability. A recent application of a Bayesian analysis led to the construction of more detailed models of the natural history of multiple sclerosis and the estimated risk of unfavorable evolution at an individual patient level.