An indirect fluorescent antibody test for Bartonella henselae, B quintana, and B elizabethae was performed in all 18 children who presented to our paediatric outpatient clinic with cat scratch disease over a six year period. Serum samples were taken on admission, after 15 days, and after six months. Diagnosis was confirmed in 15 patients (83%) and was based on seroconversion or a fourfold change of the antibody titre to B henselae in 12 patients and on a single high titre (> 128) in three patients. Lymphadenopathy was present in all patients, erythema nodosum in one, osteomyelitis in one, hepatitis in one, transverse myelitis in one, and liver or spleen granulomata, or both, in three patients. Cat scratch disease developed in autumn or winter in 12 patients. All had a history of physical contact with a cat. Our study shows that our clinical suspicion was accurate in the diagnosis of cat scratch disease in a high percentage of patients presenting to a hospital and that indirect fluorescent antibody testing for B henselae is a useful diagnostic tool.