The Global Leadership Initiative on Malnutrition (GLIM) provides a consensus-based diagnostic framework for malnutrition in hospitalized patients which includes at least one phenotypic and one etiologic criterion. In GLIM, Appendicular Skeletal Muscle based on Bioelectrical Impedance Analysis (ASMBIA) and calf circumference (CC) are two commonly techniques for muscle mass assessment, but their accuracy remains debated. Therefore, current study evaluates the prevalence of malnutrition upon hospital admission applied by GLIM criteria and mainly compares the effectiveness of ASMBIA and CC. We screened a total of 605 patients from four hospitals in Indonesia (August–October 2024). Multivariate logistic regression analyzed associations with clinical outcomes. Prevalence of malnutrition was 72.7% using three phenotypes, 55.9% with two phenotypes, 22.1% via ASMBIA, and 62.6% using CC. Significant associations (p < 0.05) were found between malnutrition and weight loss, BMI, mid-upper arm circumference (MUAC), handgrip strength (HGS), sarcopenia, and fat-free mass index (FFMI). For all criteria combinations, sensitivity was greater in CC (86.1%), followed by two phenotypes (76.8%), while the ASMBIA had the poorest sensitivity (30.5%). All GLIM-based diagnostic methods correlated with malnutrition risk screening and nutrition status indicators. The GLIM criteria provide a standardized, clinically relevant approach for diagnosing malnutrition in hospitalized patients, with CC emerging as a highly sensitive assessment to examine muscle mass.