Cardiac troponin T (TnT) is a regulatory contractile protein whose detection in the circulation has been shown to be a specific and sensitive marker for ischemic myocardial cell injury both in adult and pediatric populations. We measured serum cardiac TnT in 15 consecutive full-term neonates presenting with bradycardia and electrocardiographic features of transient myocardial ischemia. Their median TnT concentrations (0.5 microg/l, range 0.01-0.37) were statistically comparable to our laboratory reference values for healthy term newborns (median 0.17 microg/l, range 0.01-0.42) (p = NS), but significantly higher with respect to our reference limits for healthy adults (median 0.01 micog/l, range 0.01-0.1) (p < 0.05). Our data demonstrate high TnT levels in neonates during the first days of life with respect to adults and similar TnT concentrations in term infants with and without TMI.