Objective(s): This study evaluated the relationship between periapical interleukin-1β level with the levels of this inflammatory marker in gingival crevicular fluid (GCF) and serum after root canal instrumentation procedure. Materials and Methods: Samples were collected from the apical region of teeth, gingival crevicular fluid (GCF) and serum from 10 subjects with pulp necrosis and symptomatic apical periodontitis. IL-1β levels were measured using the BioLegend® Legend Max™ ELISA kit. The association between apical, gingival and serum IL-1β levels were analyzed using the Pearson product-moment correlation coefficient. Results: The mean concentrations of IL-1β from the apical region of teeth, GCF and serum, were 10.2912 pg/mL, 13.1748 pg/mL, and 13.6538 pg/mL, respectively. No significant correlation was observed between the levels of IL-1β in the periapical region of teeth, GCF and serum (P>0.05).Conclusion: It may be concluded that the inflammatory processes in the apical region of teeth may not influence the levels of inflammatory mediators in GCF or serum. Clinical Relevance: IL-1β has been known as a central mediator of periradicular and pulpal inflammation. This assessment is carried out to further understand the inflammatory process via chemokine expression in the apical, GCF and serum.