This was a midterm election, the date when the winners took office falling halfway through President Ramon Magsaysay's four-year term.

There was a separate special election held for the vacant seat of Senator Carlos P. Garcia after he won as Vice President in 1953.

Senator Claro M. Recto, one of those who actively sought the adoption of the former Defense Secretary into the NP fold in 1953, had grown critical of Magsaysay, calling him a “banana dictator” and “American puppet,” among other unflattering names.

In retaliation, Magsaysay refused the inclusion of Recto into the NP Senate slate of 1955, prompting the Batangueño leader to seek support for his candidacy with the Liberals.

Though Lorenzo Tañada of the NCP had cooperated with the NP in 1953, Recto became the first “guest candidate” in Philippine electoral history, when he was included in the Liberal Party lineup but did not resign his membership as a Nacionalista.