Multiple sclerosis (MS) is a major inflammatory and demyelinating disease of the central nervous system. Although a significant incidence and prevalence of psychological disorders in MS has been reported there is limited data on the prevalence of personality disorders (PD) in these patients. Recent findings indicate the need for early diagnosis and treatment of PD in MS patients in the interests of prognosis, conformity to treatment and patient's quality of life improvement. This article summarizes existing evidence on prevalence, types and diagnostic criteria of PD in MS, clinical manifestations of personality pathology or changes in MS patients, and instruments currently used for diagnosis and assessment of PD in this group of patients. Underlying mechanisms suggested as causes of personality changes in MS patients are also discussed. The article reviews therapeutic strategies, including pharmacotherapy and psychotherapy interventions and emphasizes the need for a multidisciplinary approach to patient's treatment.