Purpose: Among patients with multiple traumatic fractures, a tendency to form more callus exists in groups with multiple fractures combined with traumatic brain injury. This retrospective study evaluated the hematologic factors that might be useful to predict callus formation by comparing serologic tests and clinical and radiologic results in two groups. Methods: From January 2000 to December 2010, patients with femur shaft fractures were divided in two groups: one without traumatic brain injury (control group: 32 cases), and the other with traumatic brain injury (study group: 44 cases). We evaluated routine serologic exams and the amount of callus formation during the follow-up period. Results: Only the alkaline phosphatase level was statistically different between the two groups, not the White blood cell count, C-reactive protein, total calcium, and lactate dehydrogenase level. The amount of callus formation on the antero-posterior radiograph at the last follow up period was 74.9% in the study group and 42.1% in the control group. Then lateral radiograph showed 73.2% callus formation rate in the study group and 31.8% in the control group. Conclusion: In routine serologic exams, the two groups had no significant differences, except for the alkaline phosphatase level. The group with traumatic brain injury had much more callus formation, but there was no reliable factor to predict callus formation on the routine serologic exam.