Background In Ethiopia, malnutrition among older adults is under detected and, neglected area because the entire problem related with aging considered as fate of aging. Also, older adults are often omitted from public health research. Literatures are scarce in Ethiopia; there is limited information in the current study area among older adults using Min Nutritional Assessment (MNA). Therefore, this paper investigated the prevalence of malnutrition and its predictors among older adults people aged 65 years or above in Addis Ababa, Ethiopia. Methods A community-based cross-sectional study was employed from January 1 to march 30, 2020 in Addis Ababa. Nutritional status of the older adults was measured by using Min nutritional assessment (MNA). Data from 662 older adults were collected through face to face interviews using a structured questionnaire. Bivariable and multivariable logistic regression analysis was done to identify factors associated with malnutrition. Result The prevalence of malnutrition among older adults was found to be 26.6%[95% Confidence interval (CI):22.8, 30.1]. Depression [Adjusted Odds Ratio (AOR) = 7.57 95%CI: 5.01, 11.45], being poor [AOR = 1.95 95% CI: 1.166, 3.25], occupation; daily laborer and guard [AOR = 2.78 95% CI: 1.12, 7.17] and being old old [AOR = 2.62 95% CI: 1.62, 4.25] were significantly associated with the higher odds of malnutrition. Conclusion This study illustrated that considerably high proportion of older adults were malnourished in Addis Ababa. Socio-economic characteristics and depression were significantly associated with malnutrition. Therefore, nutritional and social support activities are essential for older adults, particularly of those who are socio-economically disadvantaged and advanced age. In addition, regular nutritional screening and management as well as behavioral interventions should be strengthened as a pillar component of therapeutic interventions. Specific nutritional requirements, at later stages of life is changing, and with the population aged over 65 years increasing in low-income countries like Ethiopia, the research in this field is likely to increase further.