Of the 7 Iowa incumbents, 5 were re-elected.
Iowa was reapportioned from 7 seats to 6, dividing the old 5th district around Des Moines between its neighbors. Its incumbent, Neal Smith, won again in the south-central Iowa 4th district.
|Iowa 1||Fred Schwengel||Republican||1966||Incumbent lost re-election.
New member elected.
|? Edward Mezvinsky (Democratic) 53.4%|
Fred Schwengel (Republican) 45.7%
Lee E. Foster (AI) 1.0%
|Iowa 2||John C. Culver||Democratic||1964||Incumbent re-elected.||? John C. Culver (Democratic) 59.2%|
Theodore R. Ellsworth (Republican) 40.8%
|Iowa 3||H. R. Gross||Republican||1948||Incumbent re-elected.||? H. R. Gross (Republican) 55.7%|
Lyle D. Taylor (Democratic) 44.3%
|Iowa 4||Neal Smith
Redistricted from the 5th district
|Democratic||1958||Incumbent re-elected.||? Neal Smith (Democratic) 59.2%|
John Henry Kyl (Republican) 40.8%
|John Henry Kyl||Republican||1966||Incumbent lost re-election.|
|Iowa 5||William J. Scherle
Redistricted from the 7th district
|Republican||1966||Incumbent re-elected.||? William J. Scherle (Republican) 55.3%|
Tom Harkin (Democratic) 44.7%
|Iowa 6||Wiley Mayne||Republican||1966||Incumbent re-elected.||? Wiley Mayne (Republican) 52.5%|
Berkley Bedell (Democratic) 47.5%