Aim and objective: The aim and objective of this in vitro study was to gauze the effect of MTA, MTA Plus, chitosan, and their conjugates on the cell viability of human pdl fibroblasts. Materials and methods: A primary culture of human pdl fibroblasts was obtained. Materials used were MTA, MTA Plus, chitosan, and their conjugates. Methyl-thiazol-tetrazolium (MTT) colorimetric assay and Neutral Red assay were used to evaluate the cell viability of the root end filling materials after 24 hours of setting. Optical density of adherent stained biofilm was read at 570 nm using ELISA auto reader. Cell viability was evaluated as percentage of the negative control group, which represented 100% cell viability. Statistical analyses were done with one-way ANOVA and Tukey's post hoc test. Results: Test indicates that there was no cell cytotoxicity seen in Group I (MTA) and Group II (MTA Plus), whereas mild cytotoxicity was seen in Group III (chitosan). However, in Group IV (MTA–chitosan conjugate) and Group V (MTA Plus–chitosan conjugate), proliferation of fibroblasts was seen. Conclusion: Chitosan showed a synergistic effect with MTA and MTA Plus when used as a conjugate, as no cytotoxicity was seen in both the conjugates. In fact, there was proliferation of fibroblasts seen in Group IV (MTA–chitosan conjugate) and Group V (MTA Plus–chitosan conjugate).