We used 13C MR spectroscopy to follow the metabolism of [1-13C]glucose in SCC-VII tumors of C3H/HeN mice. Six different SCC-VII tumors and six muscles of normal legs were used. Spectroscopy was carried out with the intraperitoneal injection of 100 mg of [1-13C]glucose. Six distinct resonances were detected: the alpha and beta anomers of the C1 of glucose, C2,3,4 of glutamate and glutamine, and the C3 of lactate. Signals from [1-13C]glucose were first detected in the spectra of tumor 10 minutes after injection. Signals decreased faster in the SCC-VII tumors than the muscle of normal leg. The presence of 13C of glutamate/glutamine suggested the entry of pyruvate into the TCA cycle in SCC-VII tumor. The more rapid decrease of signals from [1-13C]glucose in the SCC-VII tumor may be attributed to the effects of blood flow volume and metabolic activity.