Cat scratch disease (CSD) is a rarely recognized bacterial disease with a diverse course. Local lymphadenitis is the most frequent form, in more than 50% the course can mimic a malignant process. In very rare cases, CSD may occur in the musculoskeletal system as osteitis, artropathy or myalgia. The article describes a case of CSD, diagnosed very early and confirmed both by serologic and molecular examinations in a 10-year-old boy. The first symptoms, i.e. enlargement of lymph nodes occurred 2-3 weeks after scratch by the cat in the region of the left shoulder. The ultrasonography detected enlargement, oedema and hypervascularity of lymph nodes of the left arm and forearm. The hectic fever occurred on the 11^th day since the onset. 3 days later, the erythrocyte sedimentation rate became higher and leucocytosis occurred. CRP changed 3 weeks after the onset. Other laboratory tests were normal. Although cefetamet pivoxil was applied on the 10^th day of the disease, on the 16^th day, the abscess was formed in one of the changed lymph nodes. After the surgical treatment and netilmicin therapy, the changes were completely recovered.