Merry Christmas kids!
Up to 20 wrapped gifts, bought with the hospital's charity funds were taken between Friday and yesterday, the London Metropolitan Police said.
They included portable DVD players, DVDs, Nintendo DS games consoles, games and toys.
Inspector Neal Anderson said: "To steal presents that were supposed to be for children too sick to be at home with their families at Christmas is beyond belief.
"I would urge anyone who has information about the individual, or persons responsible, to contact officers so that we can try and get the items back before Christmas Day.
"I would also urge the thief to try and think about their actions and do the decent thing and return them."
Met Police Commissioner Bernard Hogan-Howe slammed the sick theft, saying: "They are ideal gifts for children who aren't very well and are trapped in a hospital at Christmas.
"Yet someone thinks it is a good idea to take them.
"I would like to make an appeal. If anybody knows where these are – if anybody knows who took them, please tell us."