Blatter feels the system – in use since 1965 – is dated and favours sides who travel in the second leg.
And he pointed to the example of England's end-of-season play-offs at how two-legged affairs can be decided without away goals.
Blatter wrote in his FIFA Weekly magazine column: "It is time to rethink the system.
"Football has progressed since the 1960s, so the away goals rule may now be questioned. Does the away goals rule still make sense?
"The idea dates back to a time when away games were often an adventure, involving journeys that could be long and arduous - and the playing conditions would vary considerably.
"In reality, it favours the club that play away from home in the second leg. Where the scores are tied, that team has 30 minutes more than their opponent to score a valuable away goal. After all, in the first leg there is no extra time.
"Such an imbalance has already been disposed of in various competitions. The away goals rule is no longer used in the semi-finals of the promotion play-offs in English football."
