One of Germany's foremost modern artists, the 61-year-old had been suffering from amyotrophic lateral sclerosis (ALS), a disease which attacks and destroys nerve cells in the brain.
He died in the early hours of Monday at his home in Düsseldorf, his wife, Oda Jaune-Immendorff, said.
A charismatic figure, Immendorff was known for his flamboyant lifestyle as well as for his paintings, prints and sculptures that mixed surrealism with an element of satire.
He also ventured into the world of theater -- creating set designs for the Salzburg Festival -- and once developed his own fashion line.
Art and excess
In March 1997, Immendorff was awarded the $250,000 (186,000 euro) Marco Prize of the Museum of Contemporary Art in Monterrey, Mexico, the best endowed art price in the world.
In August 2004, however, he was fined and given an 11-month suspended prison sentence by a German court after pleading guilty to offences relating to a widely publicized "cocaine orgy" at a Düsseldorf hotel.
The terminally ill artist testified that he only wanted to "go out with a fling" when he hired a hotel suite and invited several prostitutes to a party where alcohol and drugs were available in large quantities.
Immendorff became afflicted with ALS, also known as Lou Gehrig's disease, in 1998, and set up a foundation in his own name to finance medical research into the condition.
ALS leads to increasingly serious stages of paralysis and then to death when the person's respiratory system becomes paralyzed.
Born on June 14, 1945, in the north German town of Bleckede, Immendorff first gained attention in the 1970s with a series of works called " Café Deutschland" dealing with the division of Germany.
One of his most publicized works was an official portrait commissioned by Gerhard Schröder in which the former chancellor appears in a gilded head and clothes.
A professor at the Düsseldorf Academy of Art, Immendorff's last major exhibition was held at Berlin's New National Gallery in 2005 when he was confined to a wheelchair.