In 1992, reported Lyme disease cases increased, but the majority remained clustered in the northeast and midwest, and in California. The clinical syndromes associated with infection are better understood, and this information can calm public anxiety. The concept of fibromyalgia occurring after infection with Borrelia burgdorferi allows more appropriate treatment in late Lyme disease. The polymerase chain reaction is being applied to gain insights into the pathogenic mechanisms of Lyme disease. Progress has been made toward developing a vaccine through the use of animal models. Together, these advances provide clinicians with more confidence in the diagnosis and treatment of Lyme disease.