In the period 1988-1992 in the region of Vojvodina diseases caused by Borrelia burgdorferi were investigated for the first time. This investigation encompassed 398 persons with tick bites. There were 340 clinically healthy and 58 affected by Lyme borreliosis. Lyme borreliosis was registered in all age groups. The youngest patient was 5 and the oldest 75. Erythema migrans, clinical disease marker, was found in 94.8% of affected persons. Rheumatic disorders--arthralgiae were found in 3.5% and Sclerodermia circumscripta in 1.7%. Antibodies to Borrelia burgdorferi antigen were found in 46.9% of 32 patients tested by IFA test. In 55 (94.8%) patients the infestion took place in region of Vojvodina.