The European Union’s Restriction of Hazardous Substances (RoHS) legislation has had a profound impact on the electronics industry. One of the restricted substances, lead (Pb), is commonly used in alloys with tin for component finishes, printed board finishes and solders. Pb-free materials directly affect product performance, reliability and service life in many ways. There have been numerous, documented failures of electronics due to Pb-free materials in both commercial and Aerospace, Defense and High Performance (ADHP) products. Presently, there are no industry-accepted reliability models for Pb-free interconnections. The intent of IPC/PERM-2901 design guide is to assist design engineers in developing electronics that are completely Pb-free and meet the demanding requirements of ADHP systems and products. Coverage is given to Pb-free solders and solder joints, tin whiskers, printed board defects, product qualification, supply chain management, obsolescence mangement, and COTS assembly, selection and use