The aim of this study was to investigate the predisposing conditions and etiology of infective endocarditis (IE) in Icelandic children during the last ten years from 1984 to 1993. Records from all cases of IE in Iceland during this period were sampled. Vegetations were confirmed in all patients by echocardiography and in cases of culture negative IE the diagnosis was made on clinical grounds and on the response to antibiotic treatment. During this period eight children were diagnosed with IE. Five of these cases occurred in a cluster during a two months period last year (1993). Four patients had a known heart defect, three had a central venous catheter (CVC) and one patient had no factors known to predispose IE. The most common site of infection was the tricuspid valve seen in six cases, one in the aortic valve and one in the aortic arch. All patients survived without neurological sequel. A positive blood culture was obtained in six cases. The infective organisms were Staphylococcus aureus (three patients), Staphylococcus epidermitis (one patient), Streptococcus sanguis (one patient) and Candida albicans (one patient). The results show that the spectrum of IE in Icelandic children is similar to the changing spectrum elsewhere where infected CVC's are now responsible for relatively high proportion of the cases. This is most likely due to greater use of CVC's especially in neonatal intensive care units. A relatively few cases of typical IE, i.e. in children with an underlying heart lesion or following cardiac surgery, suggests effective prophylactic therapy and follow up.