is there any problem by using wireless keyboard and mouse?

like health problem?

................as they emit RF radiations By Rohit RYes
i dont think so....these raditions are not that strong i suppose...but yes u can have problem in operating ur keyboard or mouse whatever it is...tat is because the are generally communicating through IR (infra red) or bluetooth and if anything comes in between the IR port and the mouse...it wont work...also if they use bluetooth try buying a good bluetooth device with greater area coverage.....
I have never heard of such problem. I myself use a wireless keyboard and a mouse and the only problem I can think of using them is the frequent change of batteries I have to do.
yes your for ever buying battery for the damn mouse
I did use a whole last year using IR-mouse, and it was ok with my health until today. But I've switched back to old-wire-mouse, because it doesn't consume battery. I do not know with wireless keyboard.
They are safe
short of sandwiching your head between the keyboard, mouse, and receivers, the radiation levels are far too low to have any adverse health effects because they are very low voltage and range limited ... and even then, you would have to have them all taped to your head for several decades ...lol