The definition of target volumes for non-small cell lung carcinoma (NSCLC) remains a controversial topic as tradition-based approaches of the past are being critically re-evaluated in the light of the advent of three-dimensional treatment techniques, by the awareness of the poor local control achieved using current treatment fields and radiation doses, and by the major improvements in noninvasive staging that enable the gross tumor volume to be established with greater accuracy. This article reviews the current knowledge and remaining uncertainties in defining target volumes for NSCLC. The use of these new approaches may allow for improvements in the therapeutic ratio of radiotherapy in NSCLC.