The year 1804 in art involved some significant artistic events and new works.

• Sculptor Pompeo Marchesi wins a scholarship to study in Rome under Antonio Canova.
• Society of Painters in Water Colours, predecessor of the Royal Watercolour Society, founded in London by William Frederick Wells.

• Johann Friedrich Dryander – French troops before Saint-Jean-lès-Sarrebruck
• Anne-Louis Girodet de Roussy-Trioson – Dominique Jean Larrey
• Francisco Goya – Portrait of María Tomasa Palafox, Marquesa of Villafranca
• Antoine-Jean Gros – Bonaparte Visiting the Plague Victims of Jaffa
• Thomas Douglas Guest – Madonna and Child
• Jean Auguste Dominique Ingres – Bonaparte, First Consul
• Orest Kiprensky – Portrait of Adam Shvabler
• Thomas Lawrence
  • Portrait of Caroline of Brunswick
  • Portrait of Sir John Moore
  • Portrait of Sarah Siddons
• Robert Lefèvre – Portrait of Carle Vernet
• Stepan Shchukin – Portrait of Andreyan Zakharov (approximate date)
• George Stubbs – Ambrosio, a bay stallion, the property of Thomas Haworth
• Benjamin West
  • Cicero Discovering the Tomb of Archimedes
  • Thetis Bringing the Armor to Achilles (first version)^[1]
• David Wilkie
  • Pitlessie Fair
  • William Chalmers-Bethune, his wife Isabella Morison and their Daughter Isabella

The Prix de Rome had been expanded in 1803 to include musical composition as a category, but was not awarded in 1804.

• Grand Prix de Rome, painting:
• Grand Prix de Rome, sculpture:
• Grand Prix de Rome, architecture:
• Grand Prix de Rome, music: (none awarded).

• January 21 – Moritz von Schwind, Austrian painter (died 1871)
• February 21 – Charles-Joseph Traviès de Villers, French painter and caricaturist (died 1859)
• March 2 – Auguste Raffet, French illustrator and lithographer (died 1860)
• March 8 – Alvan Clark, American astronomer, telescope maker, portrait painter and engraver (died 1887)
• March 15 – Georgiana McCrae, English-born Australian painter (died 1890)
• April 4 – Andrew Nicholl, Irish painter (died 1886)
• April 16 – James Fahey, English landscape painter (died 1885)
• August 30 – Jacques Raymond Brascassat, French animal painter (died 1867)
• September 1 – John Scarlett Davis, English painter (died 1845)
• September 18 – John Steell, Scottish portrait sculptor (died 1891)
• September 27 – Anna McNeill Whistler, "Whistler's Mother" (died 1881)
• December 16 – Adèle Kindt, Belgian portrait and genre painter (died 1893)
• December 19 – Fitz Henry Lane, American luminist painter (died 1865)
• date unknown
  • Chō Kōran, Japanese poet and nanga artist (died 1879)
  • John Caspar Wild, Swiss-born American painter and lithographer (died 1846)

• January 28 – Nils Schillmark, Swedish-born painter who lived and worked in Finland (born 1745)^[2]
• February 27 - Auguste-Louis de Rossel de Cercy, French painter primarily of naval scenes (born 1736)
• March 3 – Giovanni Domenico Tiepolo, Italian painter and printmaker in etching (born 1727)^[3]
• March 5 – Francis Sartorius, English painter of horses (born 1734)
• March 18 – Louis Jean Desprez, French painter and architect (born 1743)
• June 2 – Cornelius Høyer, Danish miniature painter (born 1741)
• October – Charles Grignion the Younger, British history and portrait painter and engraver (born 1754)^[4]
• October 29 – George Morland, English painter of animals and rustic scenes (born 1763)
• November 4 – Nicola Peccheneda, Italian painter (born 1725)
• November 5 – August Friedrich Oelenhainz, German painter (born 1745)
• November 18 – Charles-Étienne Gaucher, French engraver (born 1740)^[5]
• December 12 – John Boydell, English engraver (born 1720)^[6]
• December 17 – Pierre Julien, French sculptor (born 1731)
• December 24 – Moses Haughton the elder, English designer, engraver and painter of portraits and still life (born 1734)^[7]
• date unknown
  • Peter Haas, German-Danish engraver (born 1754)
  • Liu Yong, Chinese politician and calligrapher in the Qing Dynasty (born 1719)