"He seemed to be doing very well," she said. "I was getting dressed and coming out to see him, and 20 minutes later he was gone."
His works included classics such as High Noon, The Defiant Ones and Judgment at Nuremberg.
According to his wife, actress Karen Sharpe Kramer, he died on Monday at the Motion Picture & Television Hospital in Woodland Hills, having recently developed pneumonia.
Oscars
"He seemed to be doing very well," she said. "I
was getting dressed and coming out to see him, and 20 minutes later he was gone."
Kramer's films were nominated for 80 Oscars, winning 16 in total, although none for best picture.
Victories included those for Gary Cooper (High Noon), Maximilian Schell (Judgement at Nuremberg) and Katharine Hepburn (Guess Who's Coming to Dinner).
"Stanley Kramer is one of our great filmmakers, not just for the art and passion he put on screen, but for the impact he has made on the conscience of the world," fellow director Steven Spielberg once said.
'Message' films
Throughout his career as a producer or producer-director, Kramer became renowned for tackling difficult social issues in his films.
His films dealt with thorny issues such as race, Nazi war crimes, social justice and nuclear holocaust.
Guess Who's Coming to Dinner, also starring Spencer Tracy and Sidney Poitier, dealt with white American middle-class parents coming to terms with their daughter falling in love with an African-American.
High Noon, also starring Grace Kelly, showed a man of courage standing up to evil, a lone voice among his scared community.
But Kramer himself said he had no wish to be typecast as a "message director".
Asked, then, why he took on such films, he replied: "I suppose the best answer is that emotionally I am drawn to these subjects.
"If two people came out of a theatre in Kansas City, and one said, 'You know, I never thought of it that way before' - that would satisfy me."
'Difference'
In 1963, Kramer made a rare foray into comedy with It's a Mad, Mad, Mad, Mad World.
The movie about a madcap race for buried treasure ran for longer than three hours.
The cast included an array of comic heavyweights including Milton Berle, Sid Caesar, Phil Silvers, Buster Keaton, Mickey Rooney and Terry-Thomas.
Kramer called it "the happiest experience I had with a film".
As well as Oscar nominations for his works, Kramer was himself nominated as best director three times.
In 1962, he was presented with a special Irving G Thalberg Memorial Award for his consistent work of high quality.
Legendary Hollywood actor Gregory Peck - who starred in Kramer's On the Beach - remarked: "He kept trying. Sometimes he failed, but now and then he hit, and he made a difference.''