Two senstive spectrophotometric methods were adopted for determination of two cephalosporins namely cefoperazone sodium and cefadroxil. The first method was based on coupling each of the two compounds with diazotized p-nitroaniline. The absorbance was measured at 472 nm, 474 nm for cefoperazone and cefadroxil, respectively, Bear's law was obeyed in concentration rang of 40-200 ug/ml, 8-40 µg/ml for cefoperazone and cefadroxil, respectively. Stoichiometry of the reaction was determined and the ratio of each diazo salt to both drugs was 2:1 in both cases. The second method was based on the application of differential spectrophotometry to the nitroso derivative of both drugs in acid and alkaline medium. Cefoperazone showed no chromic shift (335 nm) on alkalinization but exhibited marked hyperchromic effect, while cefadroxil showed both hyperchromic effect and bathochromic shift (300-349 nm). Calibration graphs of ΔA values versus concentration were linear in range 20-120, and 12-28 µg/ml of cefoperazone and cefadroxil, respectively. The two methods hold well their accuracy and precision when applied to the analysis of Cefobid vials and Duricef capsules.