Challenges in the differentiation of the aetiology of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have led to significant overuse of antibiotics. Serum procalcitonin, released in response to bacterial infections, but not viral infections, could possibly identify AECOPD requiring antibiotics. In this meta-analysis we assessed the clinical effectiveness of procalcitoninbased protocols to initiate or discontinue antibiotics in patients presenting with AECOPD. Based on a prospectively registered protocol, we reviewed the literature and selected randomised or quasi-randomised trials comparing procalcitonin-based protocols to initiate or discontinue antibiotics versus standard care in AECOPD. We followed Cochrane and GRADE (Grading of Recommendations, Assessment, Development and Evaluation) guidance to assess risk of bias, quality of evidence and to perform meta-analyses. We included eight trials evaluating 1062 patients with AECOPD. Procalcitonin-based protocols decreased antibiotic prescription (relative risk (RR) 0.56, 95% CI 0.43-0.73) and total antibiotic exposure (mean difference (MD) -3.83, 95% CI (-4.32--3.35)), without affecting clinical outcomes such as rate of treatment failure (RR 0.81, 0.62-1.06), length of hospitalisation (MD -0.76, -1.95-0.43), exacerbation recurrence rate (RR 0.96, 0.69-1.35) or mortality (RR 0.99, 0.58-1.69). However, the quality of the available evidence is low to moderate, because of methodological limitations and small overall study population. Procalcitonin-based protocols appear to be clinically effective; however, confirmatory trials with rigorous methodology are required.