Lyme-like illness (also known as southern tick–associated rash illness [STARI] or Masters disease) is vectored by the Lone Star tick ( Amblyomma americanum). Lyme-like illness lesions, which are similar to the erythema migrans rash of Lyme disease, tend to have lymphocytic dermal infiltrates. With the exception of Borrelia lonestari, the possible causative agent or agents of Lyme-like illness have not been cultured. More research is needed to fully understand this newly recognized zoonosis. Clinicians are encouraged to increase their knowledge and awareness of this Lyme disease mimic.