Technetium-99m (99Tcm) (v) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to image squamous cell carcinoma (SCC) of the head and neck. This study was undertaken to compare planar versus SPECT 99Tcm (v) DMSA scintigraphy in patients with head and neck SCC. Thirty-four patients were studied. Twenty-eight had SCC, and of these, four had received previous treatment with surgery or irradiation. SPECT was as sensitive and as accurate as clinical examination (but more sensitive and accurate than planar scintigraphy) in detecting which patients had cancer and which patients had primary tumours. SPECT was more sensitive and more accurate than planar scintigraphy (but less sensitive and accurate than clinical examination) in detecting lateral neck compartments with metastatic carcinoma. SPECT correctly upstaged 6% of clinically N0 necks. Although SPECT 99Tcm (v) DMSA scintigraphy improved the image quality, sensitivity and spatial resolution of the investigation, it has no role to play in the routine evaluation of patients with head and neck SCC (to include the clinically N0 neck).