Malignant cells show increased glucose uptake in vitro and in vivo. High expression of the glucose transporter-1 gene (GLUT1) has been found in many human tumor tissues. The aim of this study was to investigate the correlation between GLUT1 expression in breast carcinomas of Taiwanese patients and clinical prognostic parameters. Twenty-eight (71.8%) of the 39 breast carcinomas analyzed showed positive GLUT1 expression with different intensities: 1+, 19 cases (48.7%); 2+, 6 cases (15.4%), 3+, 3 cases (7.7%). No significant correlation was seen between GLUT1 expression and clinical prognostic parameters such as tumor size (p = 0.085), age (p = 0.4528), axillary lymph node metastasis (p = 0.9562), nuclear grade (p = 0.6895), estrogen receptor-positive (p = 1.0000), and progesterone receptor-positive (p = 0.9689).