The present work describes the simple, accurate and validated UV spectrophotometric method for determination of ceftriaxone sodium loaded in Nanoparticle formulation. The method was validated for different parameters like linearity, precision, specificity, accuracy, Limit of Detection (LOD), Limit of Quantification (LOQ) and Robustness as per ICH guidelines. A wavelength maximum of Ceftriaxone sodium in distilled water was found to be at 241 nm. The method was found to be linear in the range of 2 to 18 μg/ml with a correlation coefficient (r2) of 0.999. The accuracy of the method was studied by recovery study and % recovery was found in range of 99.27 to 100.06%. The method is simple, accurate and requires relatively inexpensive instrument. The proposed method can be successfully used for determination of Ceftriaxone sodium loaded in to Nanoparticle formulation.