There are 120 years since the myocarditis was described for the first time in children and infants. At that time, Emmet Holt said “Myocarditis may...occur at any age, even in foetal life”. We describe two cases of Coxsackie B4 neonatal myocarditis. Both appeared almost in the same period of time, at 3 and 4 week-old, female and male newborns and had a similar course. The onset was with rhythm and conduction disturbances: ventricular ectopies, nonsustained ventricular tachicardia, supraventricular tachicardia, sinoatrial block, atrioventricular block, blocked extrasystoles. From the beginning both had the myocardial enzymes persistently elevated: CK-MB and troponin T, which maintained elevated levels even at distance from the onset. No inflammatory response and no kinetics disturbancies were noted neighter at admission nor at 2 months distance from the onset. Serology for Coxsackie B4 was first in progressively increasing, then decreasing titers. MRI confirmed a small degree of myocardial oedema for both of them, compatible with focal myocarditis. They received IV immunoglobulin, 2 g/kg/one dose in the second day from admission and the rhythm and conduction problems were treated with Propafenone, 10 mg/kg/day. They did not tolerate beta blockers (aggravated cardiac blocks). After 2 weeks, the rythm disturbancies almost disapeared. They remained on maintenance treatment with propafenone for a three months period. Conclusion: Neonatal myocarditis must be taken into consideration at any paediatric age, even in asymptomatic patients. Rhythm problems could aggravate the progression towards dilated cardiomyopathy and early treatment could interrupt a possible deterioration.