Determination of CSF oligoclonal bands (OCBs) remains the most useful immunological marker in the diagnosis of MS. Measurement of immunoglobulin light chains in the CSF have been suggested to be highly sensitive and specific for MS in limited studies. Clinical data were obtained retrospectively in 160 patients who had CSF OCBs measured in the neuroimmunology department. Patients were divided into four groups based on their clinical diagnoses—MS, non-MS inflammatory diseases, noninflammatory CNS diseases and controls. Control group consisted of patients who had lumbar punctures for other conditions like BIH, migraine, MND etc. CSF and serum kappa and lambda concentrations were obtained and their relative indices calculated. A value of mean±3SD of the controls was used as the cut-off for determining the positivity. Mean (±SEM) CSF kappa concentration in control population was 0.13±0.03 mg/l. The CSF kappa concentration in the MS cohort was 8.01±1.33 mg/l (p<0.001), with much lower values obtained in the other groups. The ratio of CSF kappa/lambda concentration was significantly different in the MS group compared to the other disease groups. Although there was a tendency for higher light chain concentrations in the CSF in the more progressive MS subtypes, this was not statistically significant. The sensitivity of OCBs in MS was 88.9% and that of the total kappa-lambda index was 95.2%, potentially making this a useful investigation, especially in the OCB negative patients.