ABSTRACTThe objective of the study was to develop and evaluate the reverse phase high performance liquid chromatography (RP-HPLC) method for the quantitative determination of potential impurities of Mirabegron active pharmaceutical ingredient. The method uses Puratis C18 column (250 × 4.6mm, 5µm ) with mobile phase A consisted, 20 mM Ammonium acetate, pH adjusted to 4.5 and mobile phase B consisted methanol  with a gradient programme. The column temperature was maintained at 25 °C and the detection was carried out at 247 nm. Efficient and reproducible chromatographic separation was achieved on C18 stationary phase in gradient elution profile. The newly developed HPLC method was validated according to ICH guidelines considering three impurities to demonstrate precision, linearity, accuracy and robustness of the method. The developed HPLC method was found to be accurate and sensitive. The correlation coefficient values are greater than 0.99 for Mirabegron and its three impurities. Detection limit and quantitation limit was 0.04ppm and 0.14ppm respectively, indicating the high sensitivity of the newly developed method. Accuracy of the method was established based on the recovery obtained between 99.67% and 104.98% for all impurities. The result of robustness study also indicates that the method is robust and is unaffected by small variation in chromatographic conditions. The proposed HPLC method provides reliable, reproducible, accurate and sensitive for the quantification of Mirabegron related substances. Keywords: Mirabegron; Impurities; RP-HPLC; Validation.