A meta-analysis was performed to assess the accuracy of the procalcitonin (PCT) test for diagnosing neonatal sepsis. The major databases, MEDLINE, EMBASE and the Cochrane Library were searched for studies published between January 1996 and May 2009 that evaluated PCT as a diagnostic marker for neonatal sepsis and provided sufficient data to calculate sensitivity and specificity. Twenty-two studies were included in the analysis. Trials that evaluated the PCT test for the diagnosis of early-onset neonatal sepsis at different time points (birth, 0-12 h, 12-24 h, and 24-48 h) and late-onset neonatal sepsis (LONS) all showed moderate accuracy (Q* = 0.79, 0.86, 0.81, 0.82, and 0.77, respectively). The PCT test was more accurate than the C-reactive protein (CRP) test for the diagnosis of LONS. A sensitivity analysis found that differences in PCT assay producer, gestational age and severity of sepsis in the study population may partially explain the between-studies heterogeneity. The PCT test showed moderate accuracy in diagnosing neonatal sepsis, regardless of differences in diagnostic criteria and time points for testing. For the diagnosis of LONS, the PCT test showed better accuracy than the CRP test. PCT is a valuable additional tool for the diagnosis of neonatal sepsis.