The book aimed to providing a current understanding of the relationship between the cast microstructure and corrosion behaviour. In addition, the relationship between the homogenized microstructure and corrosion behaviour for cupronickel alloys is also part of the book.. It should be mentioned that this book is the detailed academic work in this subject studied the relationship between microstructure and corrosion resistance. The book and educational efforts are beneficial for engineering applications. The book is given through Four Chapters: chapter 1 presented the introduction. Chapter 2 presents the general knowledge related to cupronickel alloys. Chapter 3 explains the corrosion of cupronickel alloys. Chapter 4 covers the corrosion mechanism, regarding the cupronickel alloys.