Before the electoral reform of 1994, the area had been part of Iwate 2nd district where three Representatives had been elected by single non-transferable vote. In a 2017 reapportionment, Iwate lost one seat and was subdivided into three districts. The area of the old 4th district is now part of the new 3rd district[2]
The only representative for Iwate 4th district from its creation in 1996 to its abolition has been former Liberal Democratic Party secretary-general Ichirō Ozawa (LDP→JRP→NFP→LP→DPJ→LF→TPJ→PLP).