This systematic review was performed in order to determine the incidence and the severity of chronic pain at 3 and 6 months after thoracotomy based on meta-analyses. We conducted a MEDLINE, Web of Science and Google-scholar search of databases and references for English articles; 858 articles were reviewed. Meta-regression analysis based on the publication year was used to examine if the chronic pain rates changed over time. Event rates and confidence intervals with random effect models and Freeman-Tukey double arcsine variance-stabilizing transformation were obtained separately for the incidence of chronic pain based on 1,439 patients from 17 studies at 3 months and 1,354 patients from 15 studies at 6 months. The incidences of chronic pain at 3 and 6 month after thoracotomy were 57% (51% to 64%) and 47% (39% to 56%), respectively. The average severity of pain on a 0 to 100 scale at these times were 30±2 (26 to 35) and 32 ± 7 (17 to 46), respectively. Reported chronic pain rates are largely stable at both 3 and 6 months from the 1990s to the present.