AIM: To evaluate the apical microleakage of a new MT-Abased sealer; MTA Fillapex (Angelus) and compare it with ProRoot MTA (Dentsply) and AH Plus (Dentsply). METHODS: 51 single-rooted permanent teeth were selected and the roots were prepared using a rotary system. The samples were divided randomly into 3 groups (n = 15). Six roots were used as positive and negative controls. The teeth were obturated with respectively; A. AH Plus and gutta percha (DiaDent); B. MTA Fillapex and gutta percha; C. ProRoot MTA. Specimens were placed in 2% methylene blue dye for 72h. Then linear dye penetration was measured. Measurements were analysed statistically. RESULTS: MTA Fillapex group had significantly higher microleakage values (p 0.05). CONCLUSION: The sealing ability of AH Plus and MTA were similar whilst MTA Fillapex showed more microleakage than the other two materials. Key words: Apical microleakage, dye penetration, MTA Fillapex.