The year 2004 in architecture involved some significant architectural events and new buildings.

• January 28 – Transformation AGO: The Art Gallery of Ontario announces that Frank Gehry has designed a renovation and expansion of the gallery. Supposedly in the shape of an ice skate, the change is met with opposition by frequent benefactor Kenneth Thomson.
• March 24 – Demolition of the Brutalist Tricorn Centre in Portsmouth, England (1966) begins.
• June – Plans for The Cloud, a "Fourth Grace" at Liverpool Pier Head in England by Will Alsop, are abandoned.^[1]

• March 16 – Ray and Maria Stata Center at Massachusetts Institute of Technology, Cambridge, designed by Frank Gehry, is opened.
• April 8 – ARoS Aarhus Kunstmuseum (art museum) in Aarhus, Denmark, designed by Schmidt Hammer Lassen Architects, is opened.
• April 28 – 30 St Mary Axe in the City of London (the Swiss Re building), designed by Norman Foster, is completed.
• May 1 – Europa Tower in Vilnius, Lithuania, the tallest building in the Baltic States (2004–present), is opened.
• May 8 – Forum Building, by Herzog & de Meuron, inaugurated in Barcelona during the opening ceremony of the 2004 Universal Forum of Cultures.
• May 23 – Seattle Central Library, designed by Rem Koolhaas and Joshua Prince-Ramus, is opened to the public.
• July 16 – BP Pedestrian Bridge in Millennium Park in the Chicago Loop, designed by Frank Gehry, is opened.
• September – Sharp Centre for Design, Ontario College of Art & Design, Toronto, designed by Will Alsop of Alsop Architects, is completed.
• October – Jazz at Lincoln Center performance venue in New York City, designed by Rafael Viñoly, is opened.
• October 9 – Scottish Parliament Building in Edinburgh, by Enric Miralles, opened.
• October 14 – Lewis Glucksman Gallery at University College Cork, Ireland, designed by O'Donnell & Tuomey, is opened.
• November 18 – Clinton Presidential Center, Little Rock, Arkansas, by James Polshek, is opened.
• November 20 – Expansion and renovation of New York's Museum of Modern Art designed by Yoshio Taniguchi.
• November 28 – Wales Millennium Centre in Cardiff, Wales, designed by Jonathan Adams of Percy Thomas Partnership, is opened.
• December 14 – Millau Viaduct, by Norman Foster, at Millau, France is opened.
• December 17 – .
• December 31 – Taipei 101 is opened in Taiwan, and remains one of the tallest buildings in the world.
• Netherlands Embassy in Berlin opened, designed by Rem Koolhaas.
• IT University of Copenhagen opens its new building in Ørestad, Denmark, designed by Henning Larsen.
• The Chongqing World Trade Center in Chongqing, China is topped out in a ceremony.
• 30 Hudson Street, New Jersey, USA (the Goldman Sachs Tower), Jersey City's tallest building at 238 metres, is completed.
• Reconstruction of Nový Dvůr Monastery, Czech Republic, by John Pawson is completed.
• Reconstruction of Kingswood School, Dulwich, London, by De Rijke Marsh Morgan is completed.

• AIA Gold Medal – Samuel Mockbee (awarded posthumously)
• Architecture Firm Award – Lake Flato Architects
• Driehaus Prize – Demetri Porphyrios^[2]
• Emporis Skyscraper Award – Taipei 101
• Grand prix national de l'architecture – Patrick Berger
• Grand Prix de l'urbanisme – Christian de Portzamparc
• Praemium Imperiale Architecture Award – Oscar Niemeyer
• Pritzker Prize – Zaha Hadid
• Prix de l'Académie d'Architecture de France – Shigeru Ban
• Prix de l'Équerre d'Argent – Antoinette Robain and Claire Guieysse, for the Centre National de la Danse de Pantin
• RIAS Award for Architecture – Elder and Cannon Architects for St. Aloysius' College's Clavius Building, Glasgow
• RAIA Gold Medal – Gregory Burgess
• RIBA Royal Gold Medal – Rem Koolhaas
• Stirling Prize – 30 St Mary Axe, London by Foster and Partners^[3]
• Thomas Jefferson Medal in Architecture – Peter Walker
• Vincent Scully Prize – Aga Khan
• Twenty-five Year Award – East Building, National Gallery of Art

• May 27 – Sigrid Lorenzen Rupp, German American architect (born 1943)
• August 30 - E. Fay Jones, American architect (born 1921)
• September 12 – Max Abramovitz, American architect (born 1908)
• September 22 — Edward Larrabee Barnes, American architect (born 1915)

• Timeline of architecture