We report the case of a Protestant missionary who contracted tick-borne relapsing fever in 1979 while serving in the Sudan. Despite tetracycline treatment, his acute illness ran a protracted course, with migratory polyarthralgias lasting approximately 10 months. Symptoms recurred in 1984 and have persisted. At regular intervals, the patient has experienced recurrent episodes of fever, generalized fatigue, bilateral upper and lower extremity muscle weakness, and asymetric large joint polyarthralgia. Indirect fluorescent antibody testing of sera demonstrated titers of 1:16 for B. burgdorferi and 1:64 for B. hermsii, and immunoblotting confirmed past exposure to relapsing fever, but not Lyme disease. It is hypothesized that this individual's chronic symptoms have been related to relapsing fever, and that in certain situations or in select individuals, relapsing fever can be capable of producing a chronic clinical picture analogous to Lyme disease.