The present study is a retrospective cohort study. Metabolic syndrome (MetS) is a clustering of clinical findings that has been shown to increase the risk of the surgical outcomes. Our study aimed to evaluate whether MetS was a risk factor for increased perioperative outcomes in patients undergoing posterior lumbar interbody fusion (PLIF).We retrospectively analyzed patients over 18 years following elective posterior lumbar spine fusion from January 2014 to December 2018. Emergency procedures, infections, tumor, fracture, and revision surgeries were excluded. Patients were divided into 2 groups with and without MetS. The MetS was defined by having 3 of the following 4 criteria: obesity (body mass index ≥30 kg/m), dyslipidemia, hypertension, and diabetes. The follow-up period lasted up to 30 days after surgery. The outcomes of demographics, comorbidities, perioperative complications, and length of stay were compared between the 2 groups. Multivariate logistic regression analysis was used to identify perioperative outcomes that were independently associated with MetS.The overall prevalence of MetS was 12.5% (360/2880). Patients with MetS was a significantly higher risk factor for perioperative complications, and longer length of stay cmpared with patients without MetS (P < .05). The MetS group had a higher rate of cardiac complications (P = .019), pulmonary complication (P = .035), pneumonia (P = .026), cerebrovascular event (P = .023), urinary tract infection (P = .018), postoperative ICU admission (P = .02), and deep vein thrombosis (P = .029) than non-MetS group. The patients with MetS had longer hospital stays than the patients without MetS (22.16 vs 19.99 days, P < .001). Logistic regression analysis revealed that patients with MetS were more likely to experience perioperative complications (odds ratio [OR] 1.31; 95% confidence interval [CI]: 1.06-2.07; P < .001), and extend the length of stay (OR: 1.69; 95% CI: 1.25-2028; P = .001).The MetS is a significant risk factor for increased perioperative complications, and extend length of stay after PLIF. Strategies to minimize the adverse effect of MetS should be considered for these patients.