The district in its current borders was created in 1975, when the previous districts Bergheim and Cologne were merged. Becoming effective on November 1, 2003 the district was renamed from Erftkreis to Rhein-Erft-Kreis.
The coat of arms shows the lion of Jülich in the left half, as most of the area belonged to the duchy of Jülich. The right side shows the Cologne cross, which stands for the former Cologne district. On top the Erft river is depicted; the Prussian Rhine Province had the same symbol in its coat of arms.