Mexico was represented at the OTI Festival 1973 with the song "", written by Celia Bonfil, and performed by . The Mexican participating broadcaster, Televisa, selected its entry through a national televised competition with several phases. The song, that was performed in position 13, placed first out of 14 competing entries tying with the song from Peru in 10 votes, and winning the festival after applying the tie-breaking rule.
However, the national final had been won by "", written by Felipe Gil and performed by Gualberto Castro, which became ineligible for the festival since it was later proven that it had been broadcast on the radio before the permitted date. "", which had been the runner-up in the national final, was sent instead. This was the first entry from Mexico to actually participate in the OTI Festival, since the previous year's entry was disqualified and no replacement was sent.
Televisa held a national competition with three televised qualifying rounds and a final to select its debut entry for the 2th edition of the OTI Festival. This second edition of the National OTI Festival featured 23 songs, of which eight reached the final.
The shows were presented by Raúl Velasco, and were broadcast on within the show . The musical director was , who conducted the orchestra when required.
The three qualifying rounds were held on Sundays 30 September, and 7 and 14 October 1973. The eight highest-scoring entries among the 23 competing advanced to the final.
The final was held on Sunday 21 October 1973. The winner was "", written by Felipe Gil and performed by Gualberto Castro. The festival ended with a reprise of the winning entry.
On 26 October 1973, "" became ineligible for the OTI Festival since it was proven that it had been broadcast on the radio before the permitted date. The runner-up in the national final, "", written by Celia Bonfil, and performed by , was signed up for the international competition instead.
On 10 November 1973, the OTI Festival was held at the in Belo Horizonte, Brazil, hosted by TV Itacolomi on behalf of Rede Tupi, and broadcast live throughout Ibero-America.
Imelda Miller performed "" in position 13, with Chucho Ferrer conducting the event's orchestra, and placing first out of 14 competing entries, in a tie in 10 votes with "" by Gabriela de Jesús representing Peru. In the tie-breaking vote, Mexico received 7 votes and Peru 5, making "" the winning song.
Each participating broadcaster assembled a three-member jury, which each member voting for its favourite song.