Aim: This study aimed to compare the antibacterial effect of curcumin nanoparticles intracanal medicament with nano calcium hydroxide on a 21-days old Enterococcal Faecalis (E. faecalis) biofilm. Methodology: Thirty extracted single-rooted teeth were cleaned and shaped using ProTaper Next 1mm shorter from the apical foramen to size #X4 using 2.5% NaOCl irrigating solution. At the end of mechanical preparation, all canals received 5ml of 17% EDTA solution followed by 5ml of 2.5% NaOCl and finally 5ml of distilled water. Apical foramina were closed using cyanoacrylate glue and outer root surfaces were coated with nail polish. Each root canal was inoculated with 10μl of E. faecalis suspension in microtubes and incubated at 37°C for 21 days. Bacterial biofilm development was verified by scanning electron microscopic examination on the 21st day. Samples were divided into four groups. Group I 3% curcumin nanoparticle paste, Group II 5% curcumin nanoparticle paste, Group III nano calcium hydroxide and Group IV teeth were used as a negative control. The antibacterial agents were washed from the root canals after one week using 20ml sterile saline solution and dried with paper points then debris were collected using gates glidden size 5. The collected debris were transformed into separate sterile Eppendorf's containing 1mL of sterile saline and vortexed for 30s to determine the number of E. Faecalis colonies formed. Results: Results showed non-significant differences between the first three groups and significant difference with the negative control group. Conclusion: Curcumin nanoparticles are an effective antibacterial intracanal medicament.