The ATP Challenger Karlsruhe (official name: " Baden Open ") was a tennis tournament that took place annually from 2005 to 2009 in Karlsruhe and Ettlingen and was most recently endowed with 30,000 euros. It was initially part of the ITF Future Tour from 2000 to 2003 and always took place in Ettlingen. From 2005 it was part of the ATP Challenger Tour and stayed there for two years. From 2007 until the last event in 2009, the tournament moved to Karlsruhe. It was played outdoors on clay courts at both locations. Mischa Zverev is the record winner of the tournament with one title each in singles and doubles.
Due to problems with the main sponsor at the time, the tournament was no longer continued.