Rensing played 32 times for Köln in the Bundesliga last season but was unable to help the club avoid relegation to Germany's second tier in May. In total, he has made 103 appearances in the top flight to date for Köln and FC Bayern Munich, where he played between 2003 and 2010.
"Experience and quality"
Leverkusen chief executive officer Wolfgang Holzhäuser was delighted with the transfer, but stressed that the new man has not been brought in to replace current no.1 Bernd Leno.
"We have acquired a goalkeeper of quality and experience who will provide excellent back-up to Bernd Leno. We are competing in three competitions this season and in that respect the transfer makes perfect sense", Holzhäuser said.
Sporting director Rudi Völler was equally enthused by Rensing's arrival, noting, "Michael Rensing was always a key player at Köln and played exceptionally well there. His experience can help Bernd Leno achieve an even higher level of performance."