Practice guidelines have been published for the treatment of Lyme disease (LD). These guidelines have been challenged as inadequate. Two common LD management problems are antibiotic prophylaxis of deer tick bites (deer ticks may carry Borrelia burgdorferi, the spirochete that causes LD) and antibiotic treatment of erythema migrans, the pathognomonic rash of LD. A 1-page questionnaire was sent to a 13% (573/4300) sample of Connecticut physicians to define how they treat deer tick bites and erythema migrans. Questionnaires were returned by 320 (56%) of 573 physicians. Questionnaires were analyzed for the 267 physicians who saw patients with LD. Seventy (26%) of the 267 surveyed physicians prescribed antibiotic prophylaxis for patients with tick bites. B burgdorferi serology was ordered by 31% of physicians for patients with tick bites. Most surveyed physicians treated erythema migrans with doxycycline or amoxicillin for a mean of 21 days. Serology was ordered by 49% of physicians for patients with erythema migrans. Most physicians did not use prophylaxis for patients with deer tick bites. In addition, most of the physicians surveyed followed established guidelines for treating patients with erythema migrans. However, many of the physicians surveyed do serologic testing for patients with tick bites and/or erythema migrans. Serologic testing for these patients is usually not necessary.