Objective To investigate the prevalence of nutritional risk and malnutrition in hospitalized lung cancer patients in a tertiary A hospital in Chongqing.Methods From December 2013 to July 2017,2 735 consecutive lung cancer patients were admitted to the Department of Pneumology at Daping Hospital for planned anti-cancer treatment.Patients who did not complete a nutritional status assessment and who had repeated admission wcrc excluded from the study.The demographic and tumor characteristics were investigated in the 548 lung cancer inpatients who completed the study.The nutritional risk screening 2002 (NRS 2002) was used to evaluate the nutritional risk.The individual nutritional status was also evaluated using the patient-generated subjective global assessment (PG-SGA) questionnaire,anthropometry measurements and hematological measurements.The physical status was assessed by the Karnofsky performance status (KPS).Results According to the NRS 2002 score,29.56％ (162/548) of the cancer patients had nutritional risk (score ≥3).The prevalence of nutritional risk was 17.39％,15.00％,22.00％ and 36.86％,respectively,for patients with stage Ⅰ,Ⅱ,Ⅲ and Ⅳ lung cancer.Forty-four patients (9.67％) had a body mass index＜ 18.5 kg/m2 and poor general condition,and the prevalence was 6.52％,5.00％,8.67％ and 11.22％,respectively,for stages I,Ⅱ,Ⅲ and Ⅳ.A total of 107 cases (19.53％) had impaired nutritional status (indicated by a severity score of 3 in the NRS 2002).The prevalence by different stages was 10.87％ (stage Ⅰ),5.00％ (stage Ⅱ),14.67％ (stage Ⅲ) and 25.00％ (stage Ⅳ).One hundred and twenty-five patients (22.81％) had PG-SGA scores ≥ 9,with 2.19％,2.50％,12.67％,and 33.33％ of patients in stages Ⅰ,Ⅱ,Ⅲ and Ⅳ having these high scores.The KPS scores were lower in the patients with nutritional risk and malnutrition than in the patients with a normal nutritional status.Conclusions The prevalence of nutritional risk and malnutrition in patients with lung cancer were mediom.Nutritional risk screening and nutritional status assessment should be considered at the time of admission for lung cancer patients in order to ensure better outcomes of treatment.