Carnitine has two main functions, i.e., transporting long-chain fatty acids into the mitochondrial matrix for β-oxidation to provide cellular energy and modulating the rise in intramitochondrial acyl-CoA/CoA ratio, which relieves the inhibition of many intramitochondrial enzymes involving glucose and amino acid catabolism. The present study examined the acid soluble carnitine (ASCAR) acid insoluble carnitine (AICAR) and total camitine (TCAR) concentrations of 50 human brain tumor tissues and 11 normal brain tissues. The ASCAR levels significantly higher in gliomas and meningiomas than brain, however similar to brain in metastatic adenocarcinomas. AICAR levels were lower than brain in all tumors with the exception of a medullablastoma. TCAR levels were similar to brain in all tumor types. Decreased AICAR levels may be due to increased utilization of lipids or enhanced phospholipid and cholesterol synthesis which is need for increased membrane synthesis or formation of eicosanoids. Also decreased concentrations may be a reflection of carnitine and its acylesters role in preserving the physiologic membrane structure function from oxidative damage.