Background: Alzheimer’s Disease Related Dementias (ADRD) is estimated to increase up to 152 million in 2050. Dementia-related mortality increases with older age, male sex, neuropsychiatric symptoms, faster cognitive decline, physical impairment and disease severity. Malnutrition is an important ADRD complication due to its impact on several domains. Prior studies showed that malnutrition is associated with behavioral and cognitive impairment (emotional disinhibition and behavior disturbance, memory impairment) and higher mortality risk among ADRD patients. Prevalence of malnutrition is heterogeneous and may depend on disease severity. We aimed to assess the association between malnutrition and dementia severity in an outpatient cohort of Peruvians, part of the Genetic of Alzheimer’s Disease in Peruvian Population (GAPP) Study. Method: A cross-sectional study was carried out in three different sites of different altitude in Peru. We included individuals aged >50 years who attended memory clinics. We used the Mini-Nutritional Assessment (MNA) scale to assess the nutritional status, and the Clinical Dementia Rating (CDR) to grade the dementia. We stratified the nutritional status in normal (MNA score: 12-14) and malnourished or risk of malnourished (MNA: 11 or less). Result: We assessed 295 patients; mean age was 71.9 (SD: 8.3) and 68.8% were females; proportion of demented (CDR> = 1) was 23%. Prevalence of malnourishment and risk of malnourishment was 6.4% and 35%, respectively. When adjusted by demographic covariates and geographical recruitment site, we found malnourishment scores significantly associated with CDR scores (e.g. CDR 2-3: PR 2.27, 95% CI: 1.95-2.62). Malnourishment was not associated with cardiovascular risk factors or diseases. Conclusion: In our Peruvian cohort, malnourishment or risk of malnourishment was found associated with higher risk of ADRD. Prevalence of malnourishment or risk of malnourishment was in line with those reported in other South American countries. Further longitudinal studies should confirm this association.