Cat-scratch disease (CSD) is the most common cause of chronic lymphadenopathy in children and is a relatively common cause of lymphadenopathy in adults. The most common unusual complication of CSD is Parinaud's oculoglandular syndrome. The most serious complication is encephalopathy. Many new complications have been described in recent years including systemic recurrent disease, neuroretinitis, glomerulonephritis, arthropathy, Bell's palsy, and facial paralysis. Another potential complication of CSD is bacillary angioma- tosis. Bacillary angiomatosis occurs most frequently in human immunodeficiency virus-infected patients. It usually begins with an eruption of cutaneous papules or nodules, but in some patients cutaneous lesions are absent. Bacillary angiomatosis lesions have been reported in the lymph node, liver, spleen, bone marrow, soft tissue, and intestine. An unusual hepatic lesion is peliosis hepatis caused by bacillary angiomatosis bacilli in human immunodeficiency virus patients. Many of the patients with bacillary angiomatosis have had contact with cats. CSD bacilli and bacillary angiomatosis bacilli are identical in morphology and appearance in tissue sections. CSD and bacillary angiomatosis bacilli have cross-reacting epitopes in immunohistochemical stains employing rabbit anti-CSD antisera. Erythromycin and doxycycline are effective drugs for treating bacillary angiomatosis but historically have not benefited immunocompetent patients with CSD. Therapy with gentamicin or ciprofloxacin is reported to benefit children or adults with CSD. The bacillary angiomatosis agent was recently shown to be closely related to Rochalimaea quintana based on 16s ribosomal RNA homology experiments. Despite the similarities observed between CSD and bacillary angiomatosis, there remains a question as to whether they are related.