ObjectiveMalnutrition is one of the most common health concerns among the elderly population of Iran, yet previous studies in this field in Iran report varied and even contradictory malnutrition rates. Thus, this study aims to provide a pooled prevalence of malnutrition among Iranian older adults.Materials and methodsThe Scopus, ScienceDirect, SID, MagIran, Barakat Knowledge Network System, Medline (PubMed), and Google Scholar databases were searched to find related studies published between January 2000 and August 2021. A total of 835 articles were identified through the initial search. Following the PRISMA guidelines, 636 duplicate articles, 173 irrelevant articles, and an additional 4 articles at the secondary review were omitted, which resulted in a total of 22 articles remaining for analyses. The extracted data were analyzed within Comprehensive Meta-Analysis software.ResultsThe heterogeneity of the studies was evaluated using the I-2 test (I-2 = 98.7%). Publication bias was examined with the Egger's test, which was not statistically significant (P = 0.389). In the study of 9071 Iranians aged 60-90 years, the pooled prevalence of malnutrition was found to be 10.7% (95% CI 7.7-14.7%). In addition, the prevalence of malnutrition in Iranian older adults decreased with increasing sample size, which was significantly different (P < 0.05).ConclusionConsidering the high prevalence of malnutrition in Iranian older adults, it is necessary for health policy makers to undertake effective relevant training. In addition, it is vital to plan periodic screening programs for Iranian older adults.