The 24-year-old, a product of the club's academy, will stay at the Madejski Stadium until the summer of 2016.
"I'm delighted to sign a new contract and it's a fantastic feeling to commit my future to Reading Football Club," Robson-Kanu said.
"Towards the end of last season there were a lot of positives to take - the new manager coming in, the style of football we began to play, and this is obviously a club looking to get back into the Premier League and stay there.
"The manager has shown a lot of faith in me and the style of football he is getting the boys to play is going to be exciting but effective as well.
"The only direction the club is looking to go is upwards and I can't wait for the season to start now."
Robson-Kanu scored seven times in the Barclays Premier League last season and also headed his first international goal for Wales with the winner against Scotland at Hampden Park in March.