An isocratic reverse phase liquid chromatography (RP-LC) method has been developed and subsequently validated for the determination of Celecoxib in Bulk and its pharmaceutical formulation. Separation was achieved with a Symmetry RP-18 ((Make: Waters Corporation; 75 mmx4.6 mm I.D; particle size 5 μm)) Column and Potassium dihydrogen phosphate monohydrate buffer (pH adjusted to 3.0 with diluted orthophosphoric acid): methanol: acetonitrile (400:400:200) v/v as eluent at a flow rate of 0.8 mL/min. UV detection was performed at 225nm. The method is simple, rapid, and selective. The described method of Celecoxib is linear over a range of 25 μg/mL to 75 μg/mL. The method precision for the determination of assay was below 1.0% RSD. The percentage recoveries of active pharmaceutical ingredient (API) from dosage forms ranged from 98 to 102%. The results showed that the proposed method is suitable for the precise, accurate and rapid determination of Celecoxib in bulk, its capsule dosage forms.