Introduction: This is a prospective, observational study. The aims of the study were to determine the rate of bacteraemia in febrile children in Turkey, and to evaluate the usefulness of white blood cell (WBC) count and manual differential counts of peripheral blood smears and a RISK score in predicting bacteraemia among these children. Materials and Methods: A total of 377 febrile children aged 3 to 36 months were included in the study. Complete blood cell (CBC) count, manual differential counts and blood cultures were performed in all patients. The main outcome measures used to evaluate the usefulness of the RISK score were sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), odds ratio (OR), posterior probability, areas under receiver operator characteristic curves (AUC) and miss-to-diagnosis ratio (MDR). Results: Among the patients, 4.4% had bacteraemia and the predominant pathogen was Streptococcus pneumoniae. The Yale Observation Scale scores, percentages of neutrophil and bands, band-neutrophil ratio, absolute neutrophil count and absolute band count were found to be statistically significant predictors of bacteraemia. When the RISK score was 2 or higher, sensitivity was 93.8%, false positive ratio 35.8%, PPV 10.6%, NPV 99.5%, OR 26.2 (95% CI, 3.4 to 200.8), MDR 0.066 and posterior probability value 10%. Conclusions: We conclude that determination of the RISK score will significantly decrease unnecessary blood culture sampling, antibiotherapy and hospitalisation among febrile patients aged 3 to 36 months without an identifiable focus of infection.