Ninety-five patients suspected of having multiple sclerosis (MS) were evaluated by medical history and neurologic examination. Based on this evidence they were divided into three groups: clinically definite MS, not-definite MS, and not MS. The adjunct tests, chemical analysis, and magnetic resonance imaging (MRI), were also performed to assess the diagnosis of MS. Chemical analyses of paired serum and cerebrospinal fluid (CSF) samples were performed to identify oligoclonal immunoglobulin bands and to estimate both the albumin quotient and the IgG index. A positive correlation was found between the chemical test results and definite MS in 73 of 73 cases. In 11 of 12 cases of not-definite MS the chemical results were positive for MS. A positive correlation was also found between ten of ten cases that were not MS and negative chemical test results. MRI scans were positive for MS in 48 of 51 clinically definite MS cases and in 4 of 4 not-definite MS cases. MRI scans were negative for MS in five of six cases that were not MS. These findings demonstrate that combined determinations of serum and CSF proteins by simple zone electrophoresis and commercial immunochemical tests can be useful laboratory aids in the diagnosis of MS. The MRI scans provide additional evidence to support the diagnosis of MS.