Objectives: Development and Validation of an Accurate, Sensitive, Precise, and Quick Analytical Method for Determination of Percent Assay in Pazopanib Tablets 200 mg and 400 mg by Reverse Phase High Performance Chromatography. Methods: On Inertsil ODS C18,150 x 4.6 mm, 5 μm as the stationary phase, Pazopanib in bulk and formulations were evaluated. At a flow rate of 1.0 ml/min, the mobile phase was made up of Buffer solution and Acetonitrile in a 75:25 (percent v/v) ratio, respectively. Using a PDA detector with a 275 nm detection wavelength, elutes were examined. According to ICH guidelines, Validation of Analytical Procedures: Text and Methodology Q2, the suggested method was approved (R1). Results: The chromatographic peaks of Pazopanib in this investigation had good resolution with a retention duration of 3.8 min. With a 1.000 correlation coefficient, Pazopanib demonstrated remarkable linearity. The quantification of Pazopanib showed good reproducibility when other validation factors like precision, specificity, accuracy, and robustness were used. Conclusion: Reverse Phase High Performance Chromatography (RP-HPLC) was used to quickly design and validate the Analytical Method Validation for Determination of Percent Assay in Pazopanib Tablets 200 mg and 400 mg.