The monograph is devoted to the consideration of the physicochemical and technological foundations for the production of new types of urea-containing NPK and NPKS fertilizers. Information about the state and current trends in the development of the raw material base, new forms and technologies for producing phosphorus-containing complex mineral fertilizers is systematized. New scientific data are presented regarding the physicochemical features of the acid decomposition of various types of phosphate raw materials and their rheological properties depending on the composition and conditions of introduction of the starting components. Chemical and physicochemical transformations at individual stages of the technological process, as well as the chemical and mineralogical composition of products in accordance with international REACH requirements are considered. Information is provided on the production features when using various types of phosphate raw materials and their impact on the main technical and economic indicators.