Objective  To investigate the prevalence of nutritional risk, undernutrition and nutritional therapy among elderly cancer inpatients in 6 tertiary hospitals in China. Methods  Data of elderly cancer patients were analyzed and collected between March 2012 and May 2012 from 6 tertiary hospitals in China. Nutritional risk screening was conducted within 24 hours after admission using the nutrition risk screening tool NRS 2002 to investigate the incidence of nutritional risk and malnutrition as well as the application status of nutritional therapy during hospitalization. Results  Totally 1,472 consecutive cases were recruited. The total nutritional risk prevalence is 62.8% and undernutrition is 25.3%. Two subgroups were separated according to whether receiving surgery. 906 cases were included in the non-surgical group and the prevalence of nutritional risk is 61.9%; 566 cases were included in the surgical group and the prevalence of nutritional risk is 64.1%. There is statistical significance between the two groups in the prevalence of undernutrition (27.7%vs18.9%, P=0.004). The prevalence of nutritional risk, nutritional risk score≥5 and undernutrition became higher with older age. The highest prevalence of nutritional risk is in the surgical group of alimentary tumour. Surgical group of gastric caner possessed the highest nutritional risk (77.7%). Morbidity of malnutrition of all patients was more than 25%, while non-surgical group of pancreatic cancer possessed the highest undernutrition mobidity (37.5%). 458 patients with nutritional risk were administrated nutrition support (52.4%) with PN 325 cases (71.0%), EN 9 cases (4.84%), PN plus EN 110 cases (24.0%); 186 patients without nutritional risk (36.1%) were administrated nutritional support with PN 131 cases (70.5%), EN+PN 46 cases (24.7%) and 139 cases were in surgical group (74.7%). Conclusions  The prevalence of nutritional risk and undernutrition of elderly cancer patients are high. The application of parenteral nutrition is high and the indications of nutritional therapy are not standardized.