In past research, procalcitonin (PCT) and glial fibrillary acidic protein (GFAP) have been reported to be useful biomarkers in predicting neurological outcome after the return of spontaneous circulation (ROSC) following out-of-hospital cardiac arrest (CA), although they have only been studied separately. In this study, we compared the usefulness of PCT and GFAP in predicting neurological outcome. This study was a retrospective, single-center analysis, conducted in the intensive-care unit of a university hospital. Twenty-one sequential post-CA patients were included. Serum samples were collected from patients at 12 and 24 h after ROSC. Serum PCT and GFAP were measured and compared in patients with favorable and unfavorable neurological outcomes, evaluated at 6 months using the Glasgow-Pittsburgh Cerebral Performance Categories. Serum PCT was significantly higher at 12 and 24 h in patients with unfavorable outcomes (P = 0.004 and 0.002, respectively). Serum GFAP was not significantly higher at 12 and 24 h in patients with unfavorable outcomes (P = 0.118 and 0.079, respectively). The combination of PCT and GFAP showed high predictive value for unfavorable outcomes (86.7% sensitivity and 100% specificity at 12 h; 100% sensitivity and 83.3% specificity at 24 h). Serum PCT is a marker of unfavorable neurological outcome in post-CA patients, and is superior to serum GFAP in the early phase.