Chemistry is a science that deals with the composition structure and properties of substances and with the transformation that they undergo. Analytical chemistry is a branch of chemistry involved with the analysis of chemical substances. It encompasses the theory and practice of all means of acquiring information about the composition of matter. The analysis is used here in a broad sense to include identifying substances called qualitative analysis, determining the concentration or amount of substance called quantitative analysis and determining the structure of substances. Pharmaceutical analysis plays a very vital role in the Quality Assurance and quality control of Bulk Drugs. Here we developed and validated of illaprazole and domperidone by using RP-HPLC methods.