A newborn with fatal neonatal listeriosis developed septic shock, neutropenia, thrombocytopenia and profound hypoxaemia due to severe pulmonary hypertension. Tumour necrosis factor alpha, interleukin-1-beta and interferon-gamma serum concentrations were markedly elevated, suggesting the participation of these cytokines in the aetiopathogenesis of shock induced by Listeria monocytogenes in the neonate.