The openside flanker impressed while on loan from Bristol earlier this season, making nine appearances where he won widespread plaudits.
He returned to Bristol last week but has now agreed to re-join Wales’ Capital Region for next season.
Cardiff Blues chief executive Richard Holland said: “Olly impressed everybody here while on loan from Bristol and we are very happy to bring him on board for next season.
“With so many Wales internationals in our back-row he will give us real strength in depth and we look forward to welcoming him back.”
During his time in the Welsh capital, Robinson picked up two man-of-the-match awards as he provided injury cover for Sam Warburton, Ellis Jenkins and James Botham.
He is thrilled to agree a long-term deal with the Blues and is relishing the competition for places in the back-row.
Robinson said: “I absolutely loved the last two months being with Cardiff Blues. It was brilliant to be playing so much in a great league and with a great bunch of boys so I’m delighted to be offered the chance to come back.
“To compete and learn from the likes of Sam Warburton and Ellis Jenkins is a really big driver for me and if we are all pushing each other then that’s all the better for both us as players and the club.”