A Sensitive, fast, linear and accurate liquid chromatography technique was developed for the simultaneous determination of Umeclidinium and Vilanterol in Powder dosage form. The estimation was carried out using Phenomenex C18 column (150 × 4.6 mm, 5μ) with ammonium acetate: acetonitrile taken in the ratio 60:40 as mobile phase and pumped at a flow rate of 0.9 ml/min at 300C. Detection wavelength selected was 245 nm. Retention times of Umeclidinium and Vilanterol were found to be 2.219 min and 2.794 min. The method was validated in terms of linearity, precision, accuracy, limit of detection, limit of quantification as per International council for harmonization guidelines. Degradation studies performed indicated the stability of the drug. All of these analytical validation parameters were evaluated, and the percent relative standard deviations were calculated, indicating the method's suitability for determination of Umeclidinium and Vilanterol in pharmaceutical dosage form.