Introduction: This study assesses the possible existence of cognitive disorder associated with chronic diseases [fi bromyalgia (FM), rheumatoid arthritis (RA) and lupus (SLE)], and the infl uence of the variables age, educational level and psychiatric symptoms on those disorders. Materials and methods: The patients were referred by the Rheumatology Outpatient Clinic of the Hospital Universitário de Brasília (HUB), with ages ranging from 30 to 80 years, and were divided into the following three groups: FM, 13 patients; RA, 13 patients; and SLE, 11 patients. Their performance in the neuropsychological tests of memory, language, executive functions and neuropsychiatric inventory was assessed considering their type of chronic disease, educational level and age. In addition, the cutoff points of cognitive normality of population samples were compared with the patients' performances. Results: The cognitive disorders were shown to be associated with the three diseases studied, but with signifi cant differences between them. Conclusion: The variables studied (low educational level and advanced age) were associated with various degrees of impairment in the different cognitive functions in the three pathological groups. However, FM and SLE groups showed signifi cantly higher means of the neuropsychiatric symptoms of anxiety, irritability and hallucinations than the RA group in the neuropsychiatric inventory.