Positron emission tomography (PET) with [(18)F]2-fluoro-2-deoxy-D-glucose (FDG) may show negative results for bronchioloalveolar lung carcinoma. We investigated the correlation of Glut-1 glucose transporter expression with [(18)F]FDG uptake in non-small cell lung cancer. Thirty-two patients with 34 non-small cell lung cancers (7 bronchioloalveolar carcinomas, 23 non-bronchioloalveolar adenocarcinomas, 3 squamous cell carcinomas, and 1 adenosquamous cell carcinoma) were studied. Final diagnoses were established by histology (via thoracotomy) in all patients. [(18)F]FDG PET was performed 40 min after i.v. injection of 185 MBq [(18)F]FDG. For semi-quantitative analysis of [(18)F]FDG uptake, standardized uptake values (SUVs) were calculated. Glut-1 expression was studied in terms of the immunohistochemistry of paraffin sections using anti-Glut-1 antibody to determine the intensity (0-3) of Glut-1 immunoreactivity and percentage of the Glut-1-positive area. Of seven bronchioloalveolar carcinomas, six (85.7%) were negative for the expression of Glut-1, while only one (4.3%) of 23 non-bronchioloalveolar adenocarcinomas was negative (P<0.0001). The percentages of Glut-1-positive area, as well as the SUVs, were significantly lower in bronchioloalveolar carcinomas (n=7) (2.86%±7.56% and 1.25±0.75, respectively) than in non-bronchioloalveolar adenocarcinomas (n=23) (54.83%±25.64%, P<0.0001, and 3.94±1.93, P=0.001, respectively). The degree of cell differentiation correlated with the percentage of Glut-1-positive area and SUVs in adenocarcinoma of the lung. Correlations between SUVs and the intensity of Glut-1 immunoreactivity were also significant (intensities 0 and 1, n=11, SUV 1.47±0.63; intensities 2 and 3, n=23, SUV 4.78±2.13; P<0.0001). The percentage of Glut-1-positive area correlated significantly with SUVs (n=34, r=0.658, P<0.01). Overexpression of Glut-1 correlated with high [(18)F]FDG uptake. These findings suggest that Glut-1 expression is related to [(18)F]FDG uptake in non-small cell lung cancer. Glut-1 expression, as well as [(18)F]FDG uptake, correlated with the degree of cell differentiation in adenocarcinomas, and both Glut-1 expression and [(18)F]FDG uptake were significantly lower in bronchioloalveolar carcinomas than in non-bronchioloalveolar carcinomas.