Despite the development of consensus-based frameworks to define cancer cachexia, the validity and usefulness of these frameworks are relatively unknown. The aim of the present study was to study the presence of pre-cachexia and cachexia in patients with stage III nonsmall-cell lung carcinoma (NSCLC) by using a cancer-specific framework and a general framework for cachexia, and to explore the prognostic value of pre-cachexia and cachexia. In forty patients at diagnosis of stage III NSCLC, weight loss, fat-free mass, handgrip strength, anorexia and serum biochemistry, assessed before the first chemotherapy, were used to define ‘cancer cachexia’ or ‘cachexia’. The cancer-specific framework also classified for pre-cachexia and refractory cachexia. Additionally, quality of life was assessed by the European Organisation for Research and Treatment of Cancer–Quality of Life Questionnaire C30. Groups were compared using independent t tests, ANOVA, Kaplan–Meier and Cox survival analyses. Based on the cancer-specific framework, pre-cachexia was present in nine patients (23%) and cancer cachexia was present in seven patients (18%). Cancer cachexia was associated with a reduced quality of life (P = 0.03) and shorter survival (hazard ratio (HR) = 2.9; P = 0.04). When using the general framework, cachexia was present in eleven patients (28%), and was associated with a reduced quality of life (P = 0.08) and shorter survival (HR = 4.4; P = 0.001). In conclusion, pre-cachexia and cachexia are prevalent in this small population of patients at diagnosis of stage III NSCLC. For both frameworks, cachexia appears to be associated with a reduced quality of life and shorter survival. Further studies are warranted to more extensively explore the validity and prognostic value of these new frameworks in cancer patients.