This course will contribute to a better understanding of the mechanism of corrosion in ammonium carbamate solutions of urea plants.  All forms of corrosion with different morphology as well as the parameters promoting these failure modes will be elaborated on the basis of casuistries. A survey is presented of the applied materials of construction in urea plants of different licensers. A correct choice of materials of construction as well as proper design is a prerequisite for safe operation of the HP equipment in Urea plants.