Objective To investigate the influencing factors for activity of daily living (ADL)-disability in the elderly. MethodsA case-control study was performed on the elderly subjects (over 65 years old) who came from nursing homes, community health centers and general hospitals in Beijing, Shanghai, Guangzhou, Chengdu, and Chongqing. Face-to-face questionnaires and physical examinations were conducted on the participants to survey their DLA, health and nutritional statuses. ADL-Barthel index and mini-nutritional assessment short form (MNA-SF) were used for assessment of disability and nutritional status. SPSS statistics 16.0 was used to perform the statistical analysis. Chi-square test was employed for intragroup comparison, and multivariate logistic regression analysis was adopted for the influencing factors for ADL-disability. Results A total of 4929 subjects were finally enrolled in this study, and according to disability condition, they were assigned into case group (<20 points, n=379) and control group (≥60 points,n=4450). Significant discrepancies were found in age, city, institution, and comorbidities (cardiovascular and cerebrovascular diseases, digestive diseases, respiratory diseases, urinary diseases, and skeletal diseases) between the 2 groups (P<0.05). There were obvious differences in consciousness, breath, temperature, edema, mocous membrane, skin elasticity, chewing ability and tooth (P<0.05). Among the all participants, 50.90% (2509/4929) were at adequate nutritional status, 33.66% (1659/4929) at risk of malnutrition, and 15.44% (761/4929) in malnutrition. Notable differences were also seen in the nutritional status between the 2 groups (P<0.001). Multivariate logistic regression analysis showed that mental and nervous diseases (OR=3.41), poor masticatory function (OR=2.03), cardiovascular diseases (OR=1.87), over 90 years old (OR=1.84) and urinary diseases (OR=1.55) were risk factors for ADL-disability, while adequate nutritional status (OR=0.73) and digestive diseases (OR=0.51) were the protective factors. Conclusion The elderly over 90 years old, with poor masticatory function, and suffering from mental and nervous diseases, cardiovascular diseases and urinary diseases are prone to ADL-disability.