On a rainy May 22, 2004, Letizia Ortiz Rocasolano married the heir to the Spanish throne, Felipe, Prince of Asturias in the Cathedral Santa María la Real de la Almudena. She wore a custom wedding gown by Spanish designer Manuel Pertegaz (who was suggested by Queen Sofia) and shoes by Pura López. She was loaned the Prussian Diamond Tiara by her in-laws as well as a pair of diamond earrings they had given to her as a gift.

Letizia's gown featured a 4.5-meter train with a V neck and high collar. Silver and gold floral embellishments featured predominately around the bottom of gown with a few traveling up the center to the V neck. The hand embroidered, off-white silk tulle veil she wore was a gift from Felipe; it was almost as long as her train as it was 3 meters long and 2 meters wide.

Order of Splendor explained the design of the dress by Pertegaz, "He took bespoke natural silk woven with silver thread by a Valencian firm and cut it continuously from shoulder to floor, creating a gown that is slim in front and flows out into a large round train (4.5 meters, or nearly 15 feet, long) in the back."

It had been a century since the capital had hosted a royal wedding, and it was a first for the cathedral. Celebrations went on for days with foreign royals from all over in Spain for the nuptials. Some of the royals that attended included the Prince of Wales; the then Prince Willem-Alexander and Princess Máxima of the Netherlands; and King Constantine and Queen Anne-Marie of Greece (Felipe’s maternal aunt and uncle). In total 1,600 guests were in the cathedral with millions more watching from the streets and at home.

Royal Central explained, "Felipe and Letizia were able to marry in the Roman Catholic Church since it did not consider Letitia’s first marriage canonically valid as it was only a civil ceremony. Otherwise, she would have had to seek an annulment to marry the then Prince of Asturias in a Catholic ceremony."

The wedding took place less than two months after the Madrid terror attacks that had taken place at train stations in the city in March. The couple dedicated their wedding to the victims and had a bouquet of white roses taken to Atocha station - a main target of the bombings. The roses had a message from the Prince and the new Princess, "Always in our memory, Felipe and Letizia.”