And the Blues have also announced a new deal for back-row forward Josh Navidi.
Andrews, who made his international debut against the Barbarians in 2011, featured for Wales during the recent autumn Tests and is expected to be named in the squad for this season's RBS 6 Nations Championship.
"I have been here since I was 16, and I didn't want to look elsewhere as I am happy at the Blues," Andrews said.
"We have a lot of young boys mixed with some top internationals who are contracted for the next few years, so slowly we are producing a good core. It will be exciting to see it progress over the next few years."
Navidi has pledged his future to the Blues until 2016.
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