Objectives: The study aimed to evaluate the associations between anthropometric measures with body composition, in particular skeletal muscle mass, and with physical function in a cohort of geriatric outpatients. Methods: We included 572 outpatients who attended geriatric clinics at Amsterdam UMC, location VUmc, Netherlands from January 2014 to December 2015. Anthropometric measures (height, weight, body circumferences, body mass index (BMI), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR)), and physical function measures (handgrip strength (HGS), Short Physical Performance Battery (SPPB) and Timed Up and Go test (TUG)) were obtained. Body composition was analysed using bioimpedance analysis (BIA) in a subgroup of 78 patients. Gender-stratified regression analyses were performed to test associations between anthropometric measures with body composition and physical function, adjusted for age. Results: In females, BMI, WHtR and all measured body circumferences were positively associated with body fat mass (BFM) (all β≥0.64, all p≤0.001). BMI and mid-upper arm circumference were also associated with fat-free mass (FFM) (β=0.49, p=0.001; β=0.53, p=0.01), skeletal muscle mass (SMM) (β=0.39, p=0.01; β=0.44, p=0.02) and skeletal muscle index (SMI) (β=0.44, p=0.003; β=0.44, p=0.02). In males, BMI, WHR, WHtR and waist circumference were positively associated with BFM (all β≥0.54, all p≤0.02). Calf circumference was associated with FFM (β=0.46, p=0.01), SMM (β=0.47, p=0.01) and SMI (β=0.50, p=0.01). BMI and central fat anthropometric measures were inversely associated with physical function. Conclusions: Mid-upper arm circumference and calf circumference could serve as practical proxy measures for skeletal muscle mass in geriatric outpatient setting, but their associations with physical function were weak.