A spectrophotometric procedure was developed for determination of cefepime depending on the complexation of the drug with Hg2(NO3)2 in acid medium (pH 3.5) and measuring the absorbance at 263 nm. Different variables affecting the reaction were studied and optimized. Under the optimized conditions, linear relationship with good correlation coefficient (0.999) was found between the absorbance and the concentration in the range of 3.65-40 µg ml-1. The limits of detection and quantitation were 1.20 and 3.65 µg ml-1 respectively. The stoichiometry of the reaction was studied using Yoe and Jones method and was found to be 1:2 ratio for cefepime : Hg (I). The method was successfully applied for determination of cefepime in its vial with average percentage recovery of 98.95±1.079. The results were favorably compared with those of reference method. The IR study of the formed complex was done and different probabilities of the formed complexes were suggested.