This paper analyses likely Lyme disease costs incurred by patients tested in the authors' laboratory over an 18 month period, based on patient histories and test results relating to 2110 samples submitted from laboratories serving 59% of the Scottish population. Cost analysis takes account of the direct costs of consultation, laboratory tests, antibiotic treatment and management of any sequelae, as well as indirect costs of the loss of healthy time through illness. Standard costs for each element are derived from published information, and the proportions applied to each patient category are estimated from studies described elsewhere in the literature. Of the sample, 295 patients had evidence of early Lyme disease and 31 had late Lyme disease symptoms. Based on these figures, the total annual cost for Lyme disease, when projected to the whole of Scotland, is estimated to be significant at 331,000 Pounds (range 47,000-615,000 Pounds). The range is inevitably wide because it was not possible to document complete clinical and management histories on individual patients. In addition, some late Lyme disease sequelae will require management for more than 1 year, and costs are also identified that could justifiably be included for all the other patients who tested negative for Lyme disease. These data raise the question of whether there is sufficient focus on prevention and the best management of this disease.