Background: Optimization of mobile phase for high performance liquid chromatography (HPLC) is an exigent task where one factor at a time (OFAT) approach is not preferable as it is time consuming specially for multifaceted samples. The paper describes Augmented Simplex Centroid Design (ASCD) for optimization of ternary mobile phase system for reversed phase HPLC method. The proposed design was utilized for development of mobile phase composition for simultaneous estimation of curcumin and piperine present in dietary supplement. Materials and Methods: Separation was achieved on Sunniest C18 column (150 mm x 4.6 mm, 5μ). Elution was carried out using in isocratic mode using mobile phase, 0.1 % OPA: ACN: THF (52.7: 37.3: 10.0, v/v/v) at flow rate of 1 ml/min. Sample injection volume was 20 μl. Detection was carried out at 361 nm and run time was 20 min. Results: The proposed method was linear over concentration range of 1 – 6 μg/ml for both curcumin and piperine with the regression coefficient 0.9954 and 0.9575, respectively. The limit of detection of the proposed HPLC method for curcumin and piperine were found to be 0.0621 μg/ml and 0.0633 μg/ml, respectively. The limit of quantification of the proposed HPLC method for curcumin and piperine were found to be 0.1863 μg/ml and 0.1899 μg/ml, respectively. The percentage recovery of both curcumin and piperine were found to be in the range of 96.5366 –115.6833 %. The proposed method was precise and robust. Conclusion: The method was successfully applied for standardization of dietary supplement containing curcumin and piperine.