This report covers various types of prestressing steel, including some discussion on metallurgical differences, and supplements information presented in ACI 222R to include topics specifically related to prestressing steels. Deterioration mechanisms are discussed, including hydrogen embrittlement and stress-corrosion cracking. Methods to protect prestressing steel against corrosion in new construction are presented, along with a discussion of field performance of prestressed concrete structures. Finally, field evaluation and remediation techniques are presented. Appendixes present detailed information on stress-corrosion cracking and hydrogen embrittlement issues in prestressed concrete and mitigation techniques.