To compare the effect of two calcium silicate-based (Endoseal MTA and EndoSequence BC Sealer) and an epoxy resin-based (AH Plus) root canal sealer on postoperative pain following single-visit root canal treatment on molar teeth. Patients (n=90) having one first or second molar tooth diagnosed with asymptomatic irreversible pulpitis were randomly divided into three groups according to the sealer used (n=30) and were treated by two endodontists having at least 10years of experience. All patients received a single-visit root canal treatment. After the treatments, postoperative pain scores and analgesic intake were recorded at 6, 12, 24 and 48h, and 3, 4, 5, 6 and 7days. The data were analysed statistically using non-parametric Kruskal-Wallis tests (for the comparisons of the age and VAS scores), Friedman tests (for the assessments of the changes in pain scores over time), chi-squared tests (for the comparisons of categorical variables) and Spearman's correlation test (for the correlation assessments of the age and gender factors with postoperative pain; α=0.05). There were no significant differences amongst the groups in terms of postoperative pain at any time-points assessed (P>0.05) nor for analgesic intake of patients amongst the groups (P>0.05). Analgesic intake decreased significantly after 12h in all groups (P<0.05). The sealers tested in this study were associated with similar levels of postoperative pain and were associated with a similar intake of analgesics.