Abstarct: Two simple, accurate, and precise spectrophotometric methods, manipulating ratio spectra, were developed for the simultaneous determination of amaranth and ponceau 4r. These methods include constant center coupled with spectrum subtraction (CC-SS) and ratio H-point standard addition (R-HPSAM). Effevtive parameters including pH, ionic strength and type of buffer were evaluated and optimizied. In both methods, the linear range for amaranth and ponceau 4r was obtained to be 0.2-40 mg L-1. In the CC-SS and RHPSAM methods, the detection limits for amaranth and ponceau 4r were obtained, respectively, to be 0.080, 0.063, and 0.14, 0.096 mg L-1. The proposed methods have an admissible precision and accuracy for determination of amaranth and ponceau 4r in their binary mixtures in drink sample and tap water.