This study examines the cytotoxicity of Super-Bond C&B (SB-C&B), Super-Bond RC Sealer (SB-RC), MetaSEAL (Meta), and AH Plus Sealer (AH+). Freshly mixed and set materials (100 mg) were prepared in vitro and placed in cell culture medium (1 mL) for the working time and for 6 h, respectively. L929 cells seeded into 96-well plates at 5,000 cells/well were incubated with the eluted medium (200 µL) for 24 h. Cells cultured with medium alone served as the control. Cytotoxicity was evaluated by MTS assay and analyzed with ANOVA. In the freshly mixed group, the average ± SD (%) for cell viability were 66.0 ± 13.6, 55.5 ± 15.6, 10.6 ± 0.7, and 8.9 ± 2.2 for SB-C&B, SB-RC, Meta, and AH+, respectively. In the set group, the average ± SD (%) for cell viability were 100 ± 21.9, 81.8 ± 38.5, 24.9 ± 7.9, and 23.6 ± 10.0 for SB-C&B, SB-RC, Meta, and AH+, respectively. SB-C&B and SB-RC are less cytotoxic than are Meta and AH+.