Another attendant?

This one's long puzzled me too. But then, we really don't see much of the (presumably large) bedroom when Kane utters his last word. There could have been another person present.

The butler did it!!

In the movie, the butler says he heard Kane say Rosebud. On the other hand, I have to agree with some of this arguement. When he says that he heard it, he is mostly refering to another time that he heard Kane say Rosebud. Also, the way he tells the story does not make him too trustworthy, because he is just telling the story for money.

A bit of trivia about this point

Spider Robinson, the science fiction author, relates that a "friend" of his once encountered Orson Welles eating lunch and asked him this exact question. Welles apparently looked at him in shock and surprise and had no answer for him. Whether this anecdote is true or not, I think the original nit is correct. If they wanted the audience to see that the butler had overheard it, they should have shown it--I think they messed up.

Nurse was alone

I submitted the original nitpick, and I am glad to see some agreement on it. I really liked the anecdote about Orson Welles. It is surprising that they would mess up such a key scene in the movie. If there was somebody in the room, they would have been sitting in the dark, as the nurse turns the light on. Also, it would have meant they were still sitting when Kane died and the nurse came to look at him, as there was nobody standing with her. If there was someone in the room, then they displayed very strange behaviour.

The Butler did

The butler spefically states in the movie that he had heard Kane say Rosebud and then the glass ball dropped and then he knew he was dead. The butler is not shown to be in the room but there was nobody shown in the room when he dropped the glass ball. The nurse came running in after the ball was dropped.

One Timer?

There is a simple possible explanation for this, though some may consider it outside the context of the film: who's to say this is the only time that Kane ever said "rosebud"? We only see him on his deathbed for a minute or so. The butler may have heard him murmur it at some other time.

Not neccessarily

I thought about this as well but have a few ideas. The butler states he heard Kane say a single word "rosebud" 2 times. Once when his 2nd wife leaves him (after he trashes the place and picks up the snow globe in his hand and then the butler states he heard it as Kane's last word before death. It is possible that "rosebud" may NOT have been Kane's true last word but a story concocted by either the butler (who is shown to be somewhat greedy asking for money from the reporter for information) or Kane himself! The butler is shown where everyone is tallying up Kane's possessions and it is mentioned that the belongings are worth millions (an even larger amount than today's standards compared to the 40's). So it is possible that since he heard Kane say the mysterious word once, he could report it as Kane's last words (who was always a HUGE deal as news in the press we are told) to stir up some interest that no one else would know about but him for some of that cash he asked for.\r Another idea that is plausible is that we learn Kane loves only himself. Everything and the large point of the movie is that he loves only himself and wants everyone to love and remember him in an olmost godlike fashion. He could have even planted this mystery to be told after his death with his staff so that even while he was deceased the world would still be buzzing about him.\r Another idea is that 'rosebud' may never have been said as his dying breath but upon finding him dead with the snowglobe fallen from his dead fingers his staff associated his last moments having something to do with rosebud-the exact same word he said when he first grabbed the show globe.\r Those are just a few ideas.