NEUROPSYCHOLOGICAL ASSESSMENT OF PATIENTS WITH RELAPSING REMITTING MULTIPLE SCLEROSIS PRIOR TO THE USE OF IMMUNOMODULATORY DRUGS. Background: The detection of cognitive changes (CC) and psychiatric disorders in relapsing remitting multiple sclerosis (MS-RR) contributes to patient clinical monitoring. Aim: To assess the frequency and characteristics of CC and psychiatric disorders in Chilean patients with MS-RR, before starting immunomodulatory treatment. Patients and methods: Retrospective review of data that was obtained following a standard assessment protocol. It consisted in the application of the expanded scale of Kurtzke disability (EDSS), Multiple Sclerosis Functional Composite (MSFC), fatigue intensity scale of Krupp, brief repeatable battery of neuropsychological Rao (BRN-R ) and Hamilton´s depression and anxiety questionnaires. Results: We evaluated 129 patients aged between 12 and 60 years of age (69% women). Ninety four percent of patients had eight or more years of schooling. The average EDSS score was 2.83. CC were detected in 62% of participants, in at least one subtest of the BRN-R. The main changes were verbal memory and speed in the processing information. The frequency of cognitive impairment (CI), defined as at least two BRN-R subtests altered, was 36%. The figures decreased to 17% when significant major depression or associated fatigue were excluded. Depressive symptoms were observed in 58% and anxiety in 76.7%. Conclusions: The results are consistent with those described in the literature. The type of instruments used in the investigation of CC and the definition of CI in MS should be standardized.