Diagnosis of cat-scratch disease (CSD) by polymerase chain reaction (PCR) of lymph node fineneedle aspiration (FNA) and primary lesion specimens can be difficult owing to the minute amount of available material. A PCR assay specifically suited to test these specimens was developed. First, small-quantity (10 microL) samples were prepared from 17 CSD-positive and 16 CSD-negative specimens, and DNA extraction and amplification from these samples were compared using 3 methods. Sensitivity and specificity of PCR were 100% using material collected on glass microscope slides and by using Qiagen (Hilden, Germany) columns for DNA extraction. Then, this method was used to test 11 archival glass microscope slides of FNA (7 malignant neoplasms, 4 undiagnosed lymphadenitis) and 2 primary lesion specimens. Two of the 4 lymphadenitis samples and the 2 primary lesion specimens were PCR positive. The technique presented could facilitate CSD diagnosis from a wider range of clinical samples.