<b>Multiple Method Development and Validation for Simultaneous Estimation of Chlorzoxazone and Nimesulide in Bulk and Pharmaceutical Dosage Form</b> A simple, precise and accurate multiple analytical method has been developed for the simultaneous estimation of Chlorzoxazone and Nimesulide in bulk and tablet formulations by reversed phase liquid chromatographic and UV Visible spectrophotometric techniques. The chromatographic separation was achieved on C18 analytical column. A mixture of Methanol 0.1 Ortho phosphoric acid 75 25 was used as mobile phase, at a flow rate of 1mL min and detection wavelength at 295 nm. The retention time of Chlorzoxazone and Nimesulide was found to be 4.69 and 5.45 min respectively. The linear dynamic ranges for HPLC were from 2 10 µg mL and for simultaneous equation method, derivative spectroscopy, Q ratio Absorbance method, Dual wavelength it was 10 30 µg mL for both Chlorzoxazone and Nimesulide. The percentage recovery obtained for Chlorzoxazone and Nimesulide were 100.93 and 102.19 respectively for RP HPLC, 9.7 and 100.1 for simultaneous equation method of CZ and NIM respectively, 99.97 and 99.78 for derivative spectroscopy of CZ and NIM respectively, 101.37 and 99.48 for Q ratio Absorbance method of CZ and NIM respectively, 100.13 and 99.96 for dual wavelength method of CZ and NIM respectively. The validation of the proposed methods were carried out for linearity, accuracy, precision, limit of detection, limit of quantitation and robustness. The developed method can be used for routine quality control analysis of titled drugs in combination in tablet formulation. Chlorzoxazone, Nimesulide, RP HPLC, Uv spectroscopy, derivative spectroscopy, Q ratio Absorbance, Dual wavelength 944-948 Issue-2 Volume-3 Swetha Yarramsetti | A. Elphine Prabahar | Rama Rao Nadendla