The aim of the study was to investigate the pattern of glucose transporter-1 (Glut-1) expression in primary and recurrent head and neck squamous cell carcinomas (HNSCCAs) and the relation between Glut-1 expression and 2-[18F]fluoro-2-deoxy-D-glucose - positron emission tomography (FDG-PET). Standardised uptake values (SUVs) were used to evaluate FDG uptake by the tumour. Sections were stained immunohistochemically for Glut-1, which showed that high SUVs were seen in all HNSCCAs, and patients with higher T stage tumours or less well-differentiated tumours showed significantly higher SUVs than those with lower stage tumours or better-differentiated tumours (P=0.001 and 0.04, respectively). Glut-1 immunostaining was present in all cases. The Glut-1 staining index in primary HNSCCAs was significantly lower than that in recurrent HNSCCAs (P=0.03), and the index of better-differentiated tumours lower than that of poorly-differentiated tumours (P=0.02). However, there was no significant correlation between SUV(mean) and the Glut-1 staining index. In conclusion, our data suggest that high FDG uptakes were seen with overexpression of Glut-1 in primary and recurrent HNSCCAs. SUV(mean) was related to tumour T stage and grade of differentiation, which indicated that SUV was helpful in evaluating tumours. The expression of Glut-1 in recurrent HNSCCAs was higher than that in primary HNSCCAs, and in poorly-differentiated HNSCCAs higher than in better-differentiated HNSCCAs, which indicated that Glut-1 may have a useful role as a predictor for poor prognosis in HNSCCAs. However, there was no significant correlation between FDG accumulation and Glut-1 expression.