Viridans streptococci (VS) are an increasing cause of bacteraemia in neutropenic patients with cancer. Case-control studies of predisposing factors for acquisition of this infection in children are not published. Between January 1989 and December 1999, 168 episodes of bacteraemia in 161 children with fever and neutropenia of haemato-oncology origin were analysed. 15 cases (9%) in 15 patients were caused by VS. Each case patient was compared with 6 matched control patients; 2 with other Gram-positive cocci (group 2), 2 with gram-negative bacilli bacteraemia (group 3) and two children with fever and neutropenia without bacteraemia (group 4). The median age of patients was 4.1 years (range: 2-15 years). 87% of children had acute leukaemia or lymphomas. Pneumonia was the predominant clinical focus (70%). Shock was observed in 13% of patients. ARDS was observed in one child who died of this complication. Multivariate analysis of risk factors for the development of VS bacteraemia showed that two factors were independent predictors: high doses of cytosine-arabinoside (ARA-C) as part of the chemotherapy treatment (Odds Ratio (OR): 9.3; Confidence Interval (CI) 1.56-55.5) (P<0.014) and the presence of pneumonia (OR: 1.36: CI 2.27-81.9) (P<0.0043). We propose that further studies are warranted to confirm these results.