UITextField keyboard doesn't appear

Many times your code is right, it's just about the settings of your Xcode or the Simulator.

Try Toggling Keyboard Software in the Simulator

Simulator --> Hardware --> Keyboard --> Toggle Software Keyboard

OR just simply hit Command + K it would do the same thing

One thing you should check is to make sure the containing view (the UIView that contains all the controls), which is the View icon in Interface Builder nib viewer, has User Interaction Enabled checked. If the parent container doesn't have this checked, even if the individual controls do, you will see this behavior.

I already figured out by myself! I had tha UITextField in a UIViewController that gets presented from another view controller who responds to motion events, and that previous View Controller was allways the First Responder. All I had to do was everytime i leave the controller's view in viewWillDisappear:(BOOL)animated, i called [self resignFirstResponder]; and that was all.