This design criteria described in this bulletin are based on a life prediction method developed by Electric Power Research Institute as part of a program to investigate@ and quantify@ the causes of failure of dissimilar metal welds. The program included extensive research into the metallography of such welds@ compilation of a data base relating failures to service loads@ and evaluation of improved filler metals and weld configurations. Considerable technical input to the program was provided by an ad hoc task group of the Materials Properties Council. Publication of this report - WRC Bulletin No. 350 was sponsored by the Subcommittee on Elevated Temperature Design of the Pressure Vessel Research Council of the Welding Research Council.