BACKGROUND: Lyme borreliosis (LB) is the most frequently reported tick-borne infection in Europe and North America. The aim of this study was to estimate the cost-of-illness of LB in the Netherlands. We used available incidence estimates from 2010 for tick bite consultations and three symptomatic LB outcomes: erythema migrans (EM), disseminated LB and Lyme-related persisting symptoms. The cost was estimated using these incidences and the average cost per patient as derived from a patient questionnaire. We estimated the cost from a societal perspective, including healthcare cost, patient cost and production loss, using the friction cost method and a 4% annual discount rate. Tick bites and LB in 2010 led to a societal cost of €19.3 million (95% CI 15.6-23.4; 16.6 million population) for the Netherlands. Healthcare cost and production loss each constituted 48% of the total cost (€9.3 and €9.2 million/year), and patient cost 4% (€0.8 million/year). Of the total cost, 37% was related to disseminated LB, followed by 27% for persisting symptoms, 22% for tick bites and 14% for EM. Per outcome, for an individual case the mean cost of disseminated LB and Lyme-related persisting symptoms was both around €5700; for EM and GP consultations for tick bites this was €122 and €53. As an alternative to the friction cost method, the human capital method resulted in a total cost of €23.5 million/year. LB leads to a substantial societal cost. Further research should therefore focus on additional preventive interventions.