Only Burdick filed as a Dem-NPLer, and the endorsed Republican candidate was Thomas S. Kleppe, who served two terms as a Representative for North Dakota's second congressional district from 1967 to 1971. Burdick and Kleppe won the primary elections for their respective parties.
Burdick and Kleppe would face off against each other again in 1970.
Election results
1964 United States Senate election in North Dakota