The 1948 United States Senate elections were held concurrently with the election of Democratic President Harry S. Truman for a full term. The 32 seats of Class 2 were contested in regular elections, and one special election was held to fill a vacancy. Truman campaigned against an "obstructionist" Congress that had blocked many of his initiatives, and additionally, the U.S. economy recovered from the postwar recession of 1946–1947 by election day. Thus, Truman was rewarded with a Democratic gain of nine seats in the Senate, enough to give them control of the chamber. This was the last time until 2020 that Democrats flipped a chamber of Congress in a presidential election cycle.

Joseph Allen Frear Jr. was an American businessman and politician. A Democrat, he served as a United States Senator from Delaware from 1949 to 1961. He was defeated for a third term by Republican politician J. Caleb Boggs in 1960.