Objective Analyzing the association between hematologic parameters and abnormal cranial computerized tomography (CT) findings after head trauma. Material and methods A total of 287 children with isolated traumatic brain injury (TBI) were divided into the 'normal' (NG), 'linear fracture' (LFG) and 'intraparenchymal injury' groups (IPG) based on head CT findings. Demographical/clinical data and laboratory results were obtained from medical records. Results The neutrophil-lymphocyte ratio was markedly higher in the LFG (p = 0.010 and p = 0.016, respectively) and IPG (p = 0.004 and p < 0.001, respectively) compared with NG. Lower lymphocyte-monocyte ratio (p = 0.044) and higher red cell distribution width-platelet ratio (RPR) (p = 0.030) were associated with intraparenchymal injuries. Patients requiring neurosurgical intervention had higher neutrophil-lymphocyte ratio (p = 0.026) and RPR values (p = 0.031) and lower platelet counts (p = 0.035). Lower levels of erythrocytes (p = 0.005), hemoglobin (p = 0.003) and hematocrit (p = 0.002) were associated with severe TBI and unfavorable outcome (p = 0.012, p = 0.004 and p = 0.006, respectively). Conclusions Hematologic parameters are useful in predicting the presence of abnormal cranial CT findings in children with TBI in association with injury severity; surgery need and clinical outcome.