Background: We evaluated the predictive power of the C-reactive protein (CRP)/albumin ratio for intraparenchymal injury and the severity thereof in patients with head trauma. Methods: One hundred and seventy-five consecutive adult patients with head trauma admitted to our tertiary care emergency department from January to December 2017 were included in this retrospective study. The patients were divided into the following two groups: those without (group 1) and with (group 2) pathological findings related to head trauma on cranial computed tomography (CCT). The patients were also divided into two subgroups based on the presence or absence of traumatic parenchymal lesions (e.g., brain swelling, cerebral contusion, intracerebral hematoma, and pneumocephalus, defined as traumatic brain injury (TBI). Observations and Results: CCT revealed that 124 (70.8%) patients had pathological findings (CCT+), of which skull fracture was the most common (n = 50 patients). Compared to head trauma patients without pathological lesions on CCT (group 2), the mean serum CRP/albumin ratio was significantly elevated in patients with pathological lesions (group 1). Of the 175 patients, 104 (59.4%) exhibited trauma-related parenchymal lesions on CCT. Compared to head trauma patients without TBI, the mean serum CRP/albumin ratio was markedly elevated in patients with TBI. Conclusions: An increase in the serum CRP/albumin ratio in patients with TBI enables discrimination of those with and without pathological lesions on CCT. The CRP/albumin ratio might be predictive of trauma-related parenchymal lesions in patients with head trauma.