Using recently available mass sequencing and assembly technologies, we have been able to identify and quantify unique cell-free DNA motifs in the blood of patients with multiple sclerosis (MS). The most common MS clinical syndrome, relapsing-remitting MS (RRMS), is accompanied by a unique fingerprint of both inter- and intragenic cell-free circulating nucleic acids as specific DNA sequences that provide significant clinical sensitivity and specificity. Coding genes that are differentially represented in MS serum encode cytoskeletal proteins, brain-expressed regulators of growth, and receptors involved in nervous system signal transduction. Although coding genes distinguish RRMS and its clinical activity, several repeat sequences, such as the L1M family of LINE elements, are consistently different in all MS patients and clinical status versus the normal database. These data demonstrate that DNA motifs observed in serum are characteristic of RRMS and disease activity and are promising as a clinical tool in monitoring patient responses to treatment modalities.