The aim of this systematic review is to evaluate the definition of close margin in head and neck squamous cell carcinoma (HNSCC), and its possible prognostic significance. An appropriate string was run on PubMed to retrieve articles discussing the 'close' surgical margin issue in HNSCC. A double cross-check was performed on citations and full-text articles retrieved. In total, 348 articles were identified. Further references were included by using the option "Titles in your search terms" option in PubMed. 15 papers were finally included for qualitative synthesis. In vocal cord surgery of HNSCC, a close margin could be considered to be ≤1 mm, in the larynx ≤5 mm, in the oral cavity ≤4 mm, and in the oropharynx ≤5 mm. In each patient, the choice of extent of close margin should be balanced against general condition, tumor stage, and functional issues to indicate appropriate adjuvant therapy.