Objective: To assess the feasibility and clinical value of using the CellSearch system to detect circulating tumour cells in patients with advanced-stage head and neck squamous cell carcinoma. Methods: Circulating tumour cells were isolated and counted via positive selection utilising magnetically labelled anti-epithelial cell adhesion molecule and immunocytochemical staining for cytokeratin. The correlation between circulating tumour cell presence and clinical features was evaluated in nine patients newly diagnosed with advanced-stage (stage III or IV) head and neck squamous cell carcinoma. Results: Circulating tumour cells were detected in three of the nine patients (33 per cent). Circulating tumour cell positivity was more prevalent in node stage 2 to 3 patients (3 of 5, 60 per cent) than node stage 0 to 1 patients (0 of 4, 0 per cent). Recurrent or progressive disease was observed in only one of the six patients (17 per cent) without circulating tumour cells, compared with two of the three patients (67 per cent) with circulating tumour cells. Conclusion: In this preliminary study, circulating tumour cells were successfully isolated in patients with advanced-stage head and neck squamous cell carcinoma, using the CellSearch system. Further investigation is needed to evaluate the prognostic significance of circulating tumour cells.