Aim. This study aimed to evaluate the antibacterial effect of sodium hypochlorite gel and four types of intracanal medicaments. Materials and Methods. The agar diffusion method was used to evaluate the antibacterial effect of five medicaments (sodium hypochlorite gel (NaOCl), chlorhexidine gel (CHX), calcium hydroxide paste (CH), Ledermix, and Diapex plus) against Enterococcus faecalis (E. faecalis), Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli). The zone of inhibition around each medicament was measured in millimeters, after 48 hours of incubation at 37°C. The antibacterial effects of medicaments against each microbial strain and the sensitivity of microorganisms towards each medicament were compared using the one-way ANOVA and Games-Howell post hoc tests. The level of significance was set to p<0.05. Results. All medicaments showed variable inhibition zones for all bacterial strains except Diapex Plus which showed no antibacterial activity. NaOCl gel exhibited the most significant inhibition zones for all bacterial strains followed by CHX gel, Ledermix, and CH. However, the effect of CHX and CH paste against S. aureus was statistically similar, while the effect of CH against E. faecalis was significantly higher than the Ledermix. Conclusion. Sodium hypochlorite gel displayed the highest antibacterial activity among tested medicaments and can be recommended as a potent intracanal medicament. Chlorhexidine gel showed a significantly higher antibacterial effect when compared with Ledermix and calcium hydroxide. Calcium hydroxide demonstrated stronger antibacterial activity against E. faecalis than Ledermix. Diapex Plus exhibited no antibacterial effect. © 2020 Mohamed El Sayed et al.