An approach towards a use of multiphase optimization models for a decision making in milk processing industry is demonstrated. A model formation bases on analysis of a production and marketing process of cheese and milk products. The next phase in modeling is a construction of a graphical model structure based on Petry's net principle and preparation of all necessary input data for the computer handling (LOMP). A final phase in modeling is interpretation of computer calculated results (economic analysis) suitable for business decision-making. First test results validate the application of the model for further research.