Goal-line technology will be used at Euro 2016 this summer and in the Champions League from next season.
UEFA's executive committee gave the green light to introducing the system, but will also retain an extra official behind each goal.
The success of goal-line technology in the Premier League and World Cup proved crucial, especially after high-profile incidents in major competitions. Ukraine were denied a goal against England at Euro 2012, while two years earlier Frank Lampard was denied a World Cup goal for England against Germany.
UEFA's referees chief Pierluigi Collina said: "This is not a decision we have taken quickly - we have been looking at it for the last year and a half. We are convinced implementing goal-line technology will be a further step in better control of the match.
"We are happy with the additional assistant referees even if we know that from the outside their contribution is not always appreciated.
Meanwhile, UEFA will not hold an election to replace Michel Platini as its president until the appeals process against the Frenchman's eight-year ban has been exhausted.
Platini was banned along with FIFA president Sepp Blatter last month over a ?1.3million payment he received from FIFA in 2011. He has appealed to FIFA's appeals committee and is expected to go to the Court of Arbitration for Sport if that fails.
UEFA's executive committee met on Friday and decided to delay any election until the outcome of that process. Platini has already withdrawn as a candidate for next month's FIFA presidential election and UEFA's executive committee has formally backed UEFA general secretary Gianni Infantino in the election campaign.
Infantino is understood to have stressed to delegates from the 54 member associations who met in Nyon on Friday that there is no possibility of him doing a deal with rival candidate Sheikh Salman Al Khalifa, the president of Asian football, which would see the Swiss-Italian lawyer withdraw and take over as FIFA's secretary general.
Infantino also told a news conference afterwards: "I'm a candidate in the FIFA presidency until the end."
UEFA has agree to give 500,000 euros (?378,000) to support his campaign, but he insisted he was "not the UEFA candidate".
He added: "I am not the UEFA candidate, I am not the European candidate, I see myself as the candidate for football. I'm Italian, I'm Swiss, I'm European, but more than that I'm a football person and that's what the world of football needs."