In a study of 94 consecutive patients with neurophysiologically verified carpal tunnel syndrome (CTS) 7/94 had IgG and 0/94 IgM serum titers to Borrelia burgdorferi above the 98th percentile value of age and sex matched controls (n = 127). The difference in prevalence of positive IgG serum titers in patients, compared to controls, was not statistically significant. Even in patients, living in an area, highly endemic for Lyme borreliosis, routine serological screening for borrelia infection does not seem indicated in the investigation of CTS.