The decision follows a 3-3 draw at home against Rhine derby rivals Borussia Moenchengladbach on Saturday, a result that leaves Koln two points clear of St Pauli in the relegation playoff spot with only seven matches remaining in the season.
Kwasniok was appointed last June to lead the promoted side, but a recent dip in form ultimately cost the Polish-born manager his job. Since the departure of long-term coach Peter Stoger in 2017, the club has struggled to find continuity, with only Steffen Baumgart lasting more than two seasons in the dugout during that period.
"Despite the passionate and stable performances, there was a clear downward trend in our development to be seen. We have picked up too few points – that is the reality," managing director Thomas Kessler said in a press release.
Assistant Rene Wagner has been placed in charge for the club's upcoming fixtures on an interim basis.