Even though Lyme disease probably existed in Oklahoma prior to 1975 when the disease was first reported in Connecticut and even though ecological conditions favor a high prevalence, an unexpectedly low rate was evidenced in both a serological survey and the number of cases reported to the Oklahoma State Department of Health. Lyme disease does not appear to pose a significant public health threat in Oklahoma at the present time; however, the the presence of all the necessary factors for transmission and the rapidly increasing number of cases reported in nearby areas merits continued surveillance in this state. The need for consistent case definition is discussed.