Background: The success of a root canal therapy strongly depends on creating a fluid-tight apical and coronal seal. The sealing ability is a basic feature that needs to be tested for every root canal filling material or technique. Hence; the present study was undertaken for assessing the sealing ability of two different single-cone obturation systems during root canal therapy. Materials & methods: A total of 40 freshly extracted mandibular first premolars were included in the present study. Cutting of all the specimens was done below the level of cement-enamel junction. Afterwards, all the specimens were broadly divided into two study groups with 20 specimens in each group as follows: Group 1: Single cone-technique with Gutta Percha (0.06 taper) + AH Plus sealer; and Group 2: Single cone-technique with Gutta Percha (0.06 taper) + Guttaflow2. Application of the prepared sealers was done into root canals using lentulo spiral instrument. After coating with a sealer, master gutta-percha cone was placed into the root canal at the full working length. Excess Gutta-percha was cut at the orifice level with a flame-heated hand plugger and vertically compacted. Microleakage along the root canal was evaluated using the glucose leakage model. Results: Mean glucose leakage concentration among the specimens of group 1 at day 1, 1 week and 1 month time interval was found to be 0.61 mg/dl, 5.96 mg/dl and 14.11 mg/dl respectively. Significant results were obtained while comparing the mean glucose concentrations within group 1 at different time intervals. In the present study, mean glucose leakage concentration among the specimens of group 2 at day 1, 1 week and 1 month time interval was found to be 1.58 mg/dl, 4.12 mg/dl and 8.36 mg/dl respectively. Significant results were obtained while comparing the mean glucose concentrations within group 2 at different time intervals. Also while comparing between the two study groups, it was found that mean microleakage was significantly higher among specimens of group 1 at 1 week and 1 month time interval. Conclusion: Both the techniques showed some quantity of microleakage with microleakage being significantly higher in case of AH Plus sealer group. Key words: Obturation, Single cone, Root canal therapy