Cancer tissues are characterized by increased glucose uptake. 18F-fluorodeoxyglucose(FDG), a glucose analogue is used for the diagnosis of cancer in PET studies. This study was aimed to compare the glucose uptake and glucose transporter l(GLUT1) expression in various human colon cancer cells. We measured FDG uptake by cell retention study and expression of GLUTI using Western blotting. Human colon cancer cells, SNU-C2A, SNU-C4 and SNU-C5, were used. The cells were incubated with 1μCi/ml of FDG in HEPES-buffered saline for one hour. The FDG uptake of SNU-C2A,SNU-C4 and SNU-C5 were 16.8±1.36, 12.3±5.55 and 61.0±2.17cpm/μg of protein, respectively. Dose-response and time-course studies represent that FDG uptake of cancer cells were dose dependent and time dependent. The rate of FDG uptake of SNU-C2A, SNU-C4 and SNU-C5 were 0.29±0.03, 0.21±0.09 and 1.07±0.07cpm/min/μg of protein, respectively. Western blot analysis showed that the GLUT1 expression of SNU-C5 was significantly higher than those of SNU-C2A and SNU-C4. These results represent that FDG uptake into human colon cancer cells are different from each other. In addition, FDG uptake and expression of CLUT1 are closely related in human colon cancer cells.