We used instrumental methods to characterise Lyme arthropathy in 79 patients with joint involvement and history of Lyme borreliosis. All of them had arthralgia and 45 of them also had arthritis. Radiological examination has established subchondral bone sclerosis in sacroiliac joints in 68% and sacroiliitis in 29% of the examinees. Scintigraphy revealed polyarticular lesions in many cases. Ultrasound investigation has found inflammation and edema of periarticular tissues in the knee, shoulders and hips. The level of antibodies against the causative agent Borrelia (in EIA) was significantly higher in patients with marked signs of inflammation in ultrasound examination. Thus, the combined methods of examination in the diagnosis of Lyme arthritis provide the most complete information.