A proposal to reduce Davis Cup singles matches from best-of-five sets to best-of-three has not been approved by the International Tennis Federation (ITF).
The motion was backed by 63.54% of voters at the ITF AGM, just short of the required two-thirds majority.
World number one Andy Murray has previously called for matches to be shortened to increase the participation of top players.
ITF president David Haggerty said the vote result was "disappointing".
He added: "Change is needed to ensure the long-term future of these iconic and historic competitions."