The duo replaced the fired Robin Dutt for the last six games of the 2011-12 campaign, and have now been rewarded for their good work with a full-time appointment
The pair replaced Robin Dutt at the helm at the Werkself in April 2012, and guided Leverkusen to sixth place in the Bundesliga table in the final six matches of the season.
"Sascha Lewandowski and Sami Hyypia demonstrated in the last six games their ability to lead the team with a mix of expertise, charisma, hard work and composure," Leverkusen director Wolfgang Holzhauser told reporters.
"This refreshing combination has made us optimistic about moving forward. We want to work with the Lewandowski-Hyypia partnership over the next few years to further secure our position in the top three of the Bundesliga and qualify for European football."
Leverkusen's good run of form towards the end of the season ensured direct qualification for the group stage of the Europa League next term.