Objective To determine the prevalence of sarcopenia among the elderly inpatients with type 2 diabetes mellitus (T2DM) and investigate its influencing factors. Methods According to our inclusion and exclusion criteria, consecutive elderly T2DM inpatients (≥65 years old) in Geriatrics Department of Peking Union Medical College Hospital between January 2018 and December 2019 were enrolled in this study. Geriatric assessment was performed to evaluate their existing comorbidities and geriatric syndromes. SPSS statistics 24.0 was used to perform the statistical analysis. For different data types, student′s t test, Wilcoxon rank sum test, Chi-square test, or Fisher exact test was employed for intergroup comparison. Multivariate logistic regression model was applied to analyze the influencing factors of sarcopenia in the elderly type 2 diabetes mellitus (T2DM) patients. Results A total of 225 patients were finally enrolled in the study, including 59 cases complicated with sarcopenia (sarcopenia group) and 166 without (non-sarcopenia group). Compared with the patients from the non-sarcopenia group, those of the sarcopenia group were older, and had longer hospital stay, higher ratios of fall history, assisted walking, diabetic target-organ lesions and urinary incontinence, longer time of 5-times sit-to-stand, and proportion of being unable to achieve a tandem stance, and higher level of serum creatinine (all P<0.05). Lower ratio of males, lower body mass index (BMI), lower scores of mini nutritional assessment short form, activities of daily living and instrumental activities of daily living were seen in the sarcopenia group than the non-sarcopenia group (all P<0.05). There were no significant differences in the levels of fasting blood glucose, glycosylated hemoglobin, serum albumin, prealbumin and other hematological indicators (all P>0.05). Multivariate logistic regression analysis showed that low BMI (OR=0.716,95%CI 0.609-0.842, P<0.001) and assisted walking (OR=4.391,95%CI 1.167-16.512) were influencing factors of sarcopenia in elderly T2DM patients. Conclusion The prevalence of sarcopenia is quite high in hospitalized elderly T2DM patients, and it was further increased with age. For the elderly diabetic patients with low BMI and reduced physical function, attention should be paid to the screen and corresponding intervention for sarcopenia.