The purpose of this book is to study the impact of multistage marketing on the willingness of corporate customers to pay in the Iran Pharmaceutical Industry, especially, Kowsar Pharmaceutical Company. To achieve this goal, the standard questionnaire has been used to collect first-hand information. Validity of questionnaire were confirmed by the opinion of professors and experts. The population of this study includes experts of Kowsar Pharmaceutical Company, that is 700 people.248 Respondents are selected by Morgan formula as sample of population. The results of the analysis of the pathway showed that multistage marketing methods have a significant effect on the willingness of the corporate customers to pay in Kowsar Pharmaceuticals Company.