An immunocompetent 9-year-old boy with disseminated cat scratch disease involving spleen, cervical and abdominal lymph nodes, skull, and one clavicle is reported. Antibodies to Rochalimaea quintana and R. henselae were detected, at increasing, then decreasing concentration. DNA extracted from the biopsied skull lesion was amplified by polymerase chain reaction and hybridized with species-specific oligonucleotides proving the presence of R. henselae in affected tissue. Our findings suggest that R. henselae plays a pathogenic role in cat-scratch disease.