Sure!  But only under some very specific circumstances.  You can tell you' re current employer about the offer AFTER it' s actually been made.  When the offer comes, you can ask for a few days to consider it.  THEN you can tell your present employer about the offer, BUT only if you' re fully prepared to accept the new offer in the event that your present employer tells you they can' t possibly come close to matching the offer that' s been made or, worse yet, tells you to take a hike.  I think you have to also present the offer within the context of not really wanting to leave, how much you like you job, and how much you like the people with whom you work, but in light of the offer you received you have to seriously consider it.  Your present employer may make an effort to keep you - although I' d be really surprised if they offer to match a $20K increase - your present employer may wish you well in the new job, or your present employer may politely suggest that you try not to let the door hit you in the butt on the way out.  So I really wouldn' t attempt to get a raise based on a bluff that you might take this new job if your present employer doesn' t offer you more.  If you tell your present employer about the offer, you have to be prepared to accept it.  Bluffing can really backfire badly for people at times.