This study aimed to assess the antimicrobial efficacy of a novel polymeric chlorhexidine-controlled release device as an intracanal medicament. One hundred cylindrical dentin blocks prepared from human single-rooted teeth were inoculated with Enterococcus faecalis for 3 weeks. The intracanal medicaments tested were calcium hydroxide, a polymeric chlorhexidine-controlled release device (PCRD), a polymeric controlled release device without chlorhexidine (CHx), 0.2% CHx solution, and sterile saline. Dentin samples (at 200-mum and 400-mum depths) were collected from the medicated canal lumens after 1 week of medication with sterile LightSpeed files and placed in growth medium. Bacterial growth was assessed spectrophotometrically by analysis of optical density (OD) after 24 hours of incubation. The OD values at both depths were significantly lower in the PCRD group than in the other experimental groups (P < .001). These results indicate that a PCRD can be an effective intracanal medicament against E. faecalis.