Currently, the evaluation of mental disorders in patients with Systemic lupus erythematosus (SLE) is essential in the management of the illness because of their impact in morbimortality. The main purpose of this study was to determine the prevalence of mental disorders in a group of patients with SLE in a tertiary referral hospital in Quito-Ecuador. The main diffuse central nervous system psychiatric syndromes in SLE (psychosis, anxiety and mood disorders) and cognitive dysfunction were evaluated with the MINI International Neuropsychiatric Interview and the Montreal scale, respectively. This was a descriptive, cross-sectional study which included patients 15years and older diagnosed with SLE in a tertiary referral hospital in Quito, Ecuador. 85 patients diagnosed with SLE attending the internal medicine outpatient clinic during October 2017-May 2018 were included. A bivariate analysis of possible associations between these mental disorders with corticosteroid use, antiphospholipid syndrome (APS), and quality of life was also studied. Eighty-five patients, with an average age of 34.12 ± 11.5years were included, of which 94% were females. 71% of participants (60 patients) had at least one mental disorder evaluated in this study. The most frequent was cognitive impairment (n = 43, 51%) followed by anxiety disorders (n = 35, 41%), mood disorders (n = 34, 40%) and psychosis (n = 1; 1%). 38% presented mild cognitive impairment and 13% had moderate cognitive impairment. Memory and visuospatial/executive function were the most affected domains in the cognitive assessment. 38% of participants were previously diagnosed with antiphospholipid syndrome, of which 78% had a mental disorder (OR = 1.83, p = 0.2). Most patients (n = 84; 99%) were treated with corticosteroids, of these, 59 patients presented a mental disorder (OR = 0.9, p = 0.8). Associations with APS or corticosteroid use were not statistically significant. However, the multivariate regression suggests an association between presence of mental disease and quality of life. There were statistically significant alterations in anxiety/depression and pain. There is a high prevalence of neuropsychiatric syndromes in this cohort of patients. Almost ¾ of our cohort had at least one mental disorder, the most common was cognitive impairment.