Simple accurate and sensitive batch and flow injection spectrophotometric method was depicted for the determination of famotidine (FAM) in pharmaceutical formulation. The proposed method based on oxidative coupling reaction between famotidine and the organic reagent -pyro catechol- in the presence of ferric ammonium sulfate as oxidant agent to give the water soluble blue colored product with high absorptivity at a wavelength of 580nm.The molar ratio of FAM and pyro catechol was 1:1. The Optimum conditions and analytical parameters of batch reaction method were evaluated The linearity of spectrophotometric method was in the range of (15-450) μg.ml-1 with a correlation coefficient of 0.9979. The detection limit was 10.425 μg.ml-1. The flow injection method the linear range (100- 1500) μg. mL-1, and the detection limit 87.22μg .mL-1. The proposed method was applied successfully to the assay of famotidine in pharmaceutical preparation.