Parsonage-Turner syndrome, also known as acute brachial neuritis or neuralgic amyotrophy, can be caused by various infectious agents. We report on four patients who experienced Parsonage-Turner syndrome as the first manifestation of Lyme disease. The clinical picture was typical, with acute shoulder pain followed rapidly by weakness and wasting of the shoulder girdle muscles. Electrophysiological testing showed denervation. A single patient reported erythema chronicum migrans after a tick bite. Examination of the cerebrospinal fluid showed lymphocytosis and protein elevation in 3 patients. Serological tests for Lyme disease were positive in the serum in all 4 patients and in the cerebrospinal fluid in 2 patients. Antibiotic therapy ensured a favorable outcome in all 4 cases. Two patients achieved a full recovery within 6 months. Parsonage-Turner syndrome should be added to the list of manifestations of neuroborreliosis. Serological tests for Lyme disease should be performed routinely in patients with Parsonage-Turner syndrome.