An immature cellular immunity, the prolonged use of intravascular catheters and the administration of broad-spectrum antibiotics are the principal factors responsible for systemic Candida infections in premature babies. Six infants born at less than 33 weeks and weighing 1500 grams presented with signs of non-specific septicaemia; blood cultures were positive for Candida. All were cured with a treatment consisting of 5-fluorocytosine in 5 cases; amphotericin B was required in one case. This experience authorizes us to recommend 5-fluorocytosine as first-choice treatment of systemic candidiasis in premature babies. We also believe that priority should be given to a policy of eradication of Candida in all neonatology units.