In search of biological marker in multiple sclerosis (MS), total-tau and phospho-tau (Thr181) concentrations were established in CSF and serum of 78 patients with MS, using commercially available kits. Serum and CSF concentrations of IgG, IgM, and albumin were assayed simultaneously to calculate quotients and indices of intrathecal synthesis. Serum t-tau detection was strikingly low (23.1%); therefore, this factor was excluded from further analysis. Serum p-tau levels did not correlate with any of indices or quotients. Unexpectedly, CSF t-tau and p-tau showed an inverse relation with MSSS and EDSS, which has not been published elsewhere. Our results do not support utility of serum t-tau and p-tau as surrogate markers for MS.