PURPOSE: With an increasing number of anterior cervical discectomy and fusion (ACDF) being conducted for degenerative cervical disc disease, there is a rising interest in the related quality of management and healthcare costs. Unplanned readmission after ACDF affects both the quality of management and medical expenses. This meta-analysis was performed to evaluate the risk factors of unplanned readmission after ACDF to improve the quality of management and prevent increase in healthcare costs. MATERIALS AND METHODS: We searched the databases of PubMed, EMBASE, Web of Science, and Cochrane Library to identify eligible studies using the searching terms, "readmission" and "ACDF." A total of 10 studies were included. RESULTS: Among the demographic risk factors, older age [weighted mean difference (WMD), 3.93; 95% confidence interval (CI), 2.30-5.56; p<0.001], male [odds ratio (OR), 1.23; 95% CI, 1.10-1.36; p<0.001], and private insurance (OR, 0.34; 95% CI, 0.17-0.69; p<0.001) were significantly associated with unplanned readmission. Among patient characteristics, hypertension (HTN) (OR, 2.14; 95% CI, 1.41-3.25; p<0.001), diabetes mellitus (DM) (OR, 1.59; 95% CI, 1.20-2.11; p=0.001), coronary artery disease (CAD) (OR, 2.87; 95% CI, 2.13-3.86; p<0.001), American Society of Anesthesiologists (ASA) physical status grade >2 (OR, 2.13; 95% CI, 1.68-2.72; p<0.001), and anxiety and depression (OR, 1.39; 95% CI, 1.29-1.51; p<0.001) were significantly associated with unplanned readmission. Among the perioperative factors, pulmonary complications (OR, 22.52; 95% CI, 7.21-70.41; p<0.001) was significantly associated with unplanned readmission. CONCLUSION: Male, older age, HTN, DM, CAD, ASA grade >2, anxiety and depression, pulmonary complications were significantly associated with an increased occurrence of unplanned readmission after ACDF.