John J. Dempsey Democratic Joseph Montoya Democratic The 1957 New Mexico's at-large congressional district special election was held on Tuesday April 9, 1957 to fill the vacancy caused by the death of At-Large representative John J. Dempsey.

Lieutenant Governor Joseph Montoya won the special election by a margin of 6.04 percentage points.

He would continue to represent New Mexico's at-large congressional district until 1964.