Dame Rosemary Butler said it was "critical" that people voted, with more powers coming to Wales.
She said fewer than half of those eligible to vote did so in 2011.
"Yet when I tell people that around Â£16bn is spent on things like health and education, they quickly take an interest in how that money should be spent," she said.
Elections for the assembly and police and crime commissioners take place on  5 May.
There are concerns that up to 70,000 people in Wales - the number of voters in a typical constituency - have not registered to vote out of an adult population of 2.3m.
Speaking on National Voter Registration Day on Friday, Dame Rosemary said: "Encouraging more people to vote has been a key part of my role as Presiding Officer through campaigns like Women in Public Life, and tackling the democratic deficit.
"Devolution in Wales is moving into a new era with more powers set to lie here and more decisions made in Wales, for Wales."
Rhydian Thomas, head of the Electoral Commission in Wales, said they were fully behind the drive to recruit more voters.
"It's a fantastic opportunity to spread the message that young people, students, renters and home-movers are still much less likely to be registered to vote," he said.
Details of how to register to vote are available online.

The England centre, 24, whose deal at Welford Road runs out next summer, is attracting interest from several sides.
"We are having some very positive discussions with Manu and and we are very positive about him staying here," Cockerill told BBC Radio Leicester.
"Manu is world class. Clearly people are trying to lure him to smaller clubs by offering him huge amounts of money."
Reports had suggested Tuilagi had been offered £1.6 million over three years by Worcester Warriors, although Warriors director of rugby Dean Ryan said on Wednesday there was no truth in the claims.
Wasps director of rugby Dai Young also said his club have made no move for the England centre, but Saracens, Bristol and Toulouse are also thought to be interested.
Samoa-born Tuilagi, who joined Leicester as a youngster and has since won 25 caps for England, has been offered a new deal by the Tigers.
"I didn't think other clubs were allowed to speak with him until 1 January, so that surprises me," Cockerill added.
"Manu is a sensible lad and I am sure we will come to a sensible conclusion and all indications are that it's the case.
"I am confident that Manu will stay. He has a lot of rugby left in him.
"He is a good lad. We have looked after him very well and we are confident he will stay a Leicester player."

Coventry University's Scarborough campus has been built on the town's former Weaponness Park and Ride site.
About 200 students have begun courses at the site, though it is expected to eventually be home to more than 2,000 students.
The building, which includes engineering and science labs, a mock law court and a library, is part of a £50m sports and education facility.
Professor Craig Gaskell said: "Launching our new state-of-the-art building is a huge milestone for us and demonstrates our commitment to Scarborough and the Yorkshire coast area."
A new University Technical College has been built nearby and Scarborough Athletic FC's new 2,000-seater stadium is also under construction on the site.
Coventry University also has a campus near London's Liverpool Street Station and recently announced it will open a campus in Dagenham in September 2017.

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21 February 2015 Last updated at 13:18 GMT
Mo Farah was a big star of the London 2012 Olympic Games.
He started athletics aged 12 and went on to win two gold medals at London 2012.
Now he has his sights set on the next Olympic Games, Rio 2016.
He shared his tips for young athletes with Newsround.
Mo said: "Focus on yourself. You don't become a better athlete if you have one bad race."
"Keep working, listen to coach and believe in yourself," he added.
The assembly's presiding officer is urging people to make sure they are registered to vote in May's elections.
[NEXT_CONCEPT]
Leicester director of rugby Richard Cockerill believes other clubs are offering big money to Manu Tuilagi.
[NEXT_CONCEPT]
A new £14m university campus has opened in Scarborough.
[NEXT_CONCEPT]
Athletics stars Mo Farah and Greg Rutherford have shared their tips for young athletes with Newsround.