ABSTRACT The goal of this research was to examine the compressive strengths of three pulp capping materials (Theracal, visible light-cured calcium hydroxide liner (VLC dycal), and mineral trioxide aggregate (MTA)) during three time periods. Methods: Thirty specimens from each of Theracal, VLC Dycal and MTA were fabricate using Teflon molds. The spec-imens removed from the molds and kept in 100% humidity at 37 Cº for 24 h, 7 and 28 days. The compressive strength then measured using a Universal Testing Machine for ten specimens of each materials in each testing peri-od (24 h, 7 and 28 days). The maximum load in newton obtained and then the compressive strength value in MPa calculated. The data then analyzed using ANOVA and Tukey's test. Results: VLC dycal after 28 days showed the highest compressive strength value while MTA in 24 h measuring peri-od showed the lowers compressive strength value. Two way ANOVA presented that the type of liner affected the compressive strength significantly (P < .05). Tukey’s HSD test showed the VLC dycal has higher compressive strength (P < .05) in all tested periods followed by TheraCal LC while MTA has lowest compressive strength (P < .05) in all tested periods. In addition, The Two-way ANOVA presented that the time also affected on compressive strength sig-nificantly (P < .05). Tukey’s HSD test showed VLC dycal and MTA is signifigslly higher after 28 days, while TheraCal LC is signifigslly higher after 24 h. Conclusions: The VLC dycal show the highest compressive strength than the other pulp capping liners in the three testing period, while the MTA show the lowers compressive strength. The compressive strength in both VLC dycal and MTA were increase with time while in TheraCal LC the compressive strength is decreasing with time.