Aim and Objective: The objective of this work was to develop and validate a high performance liquid chromatography (HPLC) method for the quantitative analysis of melphalan, an anticancer drug from lyophilized nanosuspension. Material and Method: Chromatographic separation was achieved by using a reverse-phase C 18 column (150 mm ×4.6 mm, pore size 5 μm, Phenomenex). The mobile phase was optimized as acetic acid, water and methanol (1: 49.5: 49.5) with pH 4 at a flow rate of 1 mL/min. The melphalan was detected and quantitated using a UV detector at a wavelength of 254 nm. Result: The method was shown to be specific and linear in the range of 10-50 μg.mL -1 with correlation coefficient of 0.9979 and was precise at the intra-day level as reflected by relative standard deviation, accurate at recovery rate 99.75±0.08 and robust to change mobile phase and column brand. The detection and quantitation limits were 0.2956 μg.mL -1 and 0.5874 μg.mL -1 , respectively. The proposed method could be advantageous in estimation of melphalan quantitation in lyophilized nanosuspension form in the presence of excipients. Conclusion: The method was found to be simple, specific, rapid, precise, accurate and reproducible. The method was successfully applied for determination of the entrapment efficiency of melphalan from lyophilized nanosuspension and was found to 93.56 ± 4.32%.