Omeprazole is a widely used proton pump inhibitor prescribed for the treatment of dyspepsia, peptic ulcer disease, gastro esophageal reflux disease, laryngo pharyngeal reflux and Zollinger-Ellison syndrome. A new ultra performance liquid chromatographic (UPLC) method was developed and validated for the quantitative analysis of omeprazole in a capsule dosage form. The separation and analysis of the related drug in the presence of ondansetron as internal standard (IS) were performed on Waters UPLC BEH C18 column (50 mm × 2.1 mm i.d., 1.7 μm) using a mobile phase consisting of acetonitrile and 0.05 M H3PO4 (28:72 v/v). Flow rate of the used mobile phase was 0.28 mL/min. The retention time for omeprazole and internal standard was found to be 0.787 and 1.060 min, respectively. A calibration graph for omeprazole in the concentration range of 4-46 μg/mL was obtained by using peak area ratio of omeprazole and internal standard in their chromatogram obtained by the detection at 302 nm. In the method validation process, percent mean recovery and relative standard deviation was found as 101.6 % and 1.20 %, respectively. It was observed that the application of the newly developed UPLC method gave us successful results for the quantitative estimation of omeprazole in capsules.