BACKGROUND Glycoconjugate molecules expressed at the plasma membrane of mammalian cells have been reported to be associated with tumor progression. The measurement of total sialic acid (TSA) and lipid-bound sialic acid (LBSA) in the cerebrospinal fluid (CSF) is suggested to be useful for the diagnosis of brain tumors. But there are very few reports available on the serum glycoconjugate levels in patients with brain tumors. OBJECTIVE The objective of this study is to check the feasibility of using serum glycoconjugates such as TSA and LBSA as tumor markers in brain tumor patients. METHODS Colorimetric estimation of TSA using diphenylamine was done on 100 patients with intracranial tumors; follow-up study was carried out in 24 cases. The LBSA fraction was isolated from the serum of 68 brain tumor patients and evaluated using phosphotungstic acid and resorcinol; follow-up study was done on 23 patients. The various types of brain tumors included in this study were glioma, meningioma, and acoustic neurinoma as well as some other types such as medulloblastoma, secondary tumors, and craniopharyngioma. RESULTS There was no significant difference between the TSA and LBSA concentrations seen in pretreatment or post-treatment cases and that seen in control subjects. CONCLUSIONS TSA and LBSA do not have the ability to discriminate between benign and malignant brain tumors. TSA and LBSA appear to be tumor markers of very limited value in patients with brain tumors.