NTRODUCTION: Root canal obturation can be time consuming and complicated. GuttaFlow is suggested for use with a simple, single cone obturating technique. AIMS AND OBJECTIVES: The aim of this study was to evaluate whether GuttaFlow and a single GP cone would produce an effective seal. METHODS: Three experimental groups were used. Group one was obturated with GP using lateral condensation, group two with GP using vertical condensation and group three using GuttaFlow and a single GP cone. Bacterial micro-leakage was tested using the two-chamber method, followed by dye penetration testing. Data was subjected to statistical analysis using the Chi Square test. RESULTS: There was no significant difference between GP using lateral condensation and GuttaFlow using a single cone for bacteria (p=0.8989) or dye (p=0.7489). GP using lateral condensation performed better than GP using vertical condensation for bacteria (p=0.0003) and dye (p=0.0006). GuttaFlow using a single cone also performed better than GP using vertical condensation for bacteria (p=0.0003) and dye (p=0.0004). CONCLUSIONS: The micro-leakage of GuttaFlow using a single cone technique is similar to that of GP using lateral condensation and less than that of GP using vertical condensation as used in this study.