The Roode Beek, also Rode Beek (German: Rodebach or Rothenbach), is a stream in the Dutch-German border area. It is a tributary of the Geleenbeek and flows through the German Kreis Heinsberg and the Dutch province of Limburg. The stream has two upper courses: a right upper course that rises near Siepenbusch, a village in the German municipality of Übach-Palenberg, and a left upper course that rises in the Brunssummerheide nature reserve, southeast of Brunssum. Both branches merge at Mindergangelt and then continue as one stream that flows into the Geleenbeek at Dieteren. The Roode Beek has a number of small side streams, including the flooded stream that used to flow through the center of Brunssum, the Merkelbekerbeek (Merkelbeek) and the Ruischerbeekje. In several places the stream forms the national border between the Netherlands and Germany. The area of the Roode Beek forms, in addition to that of the Geul and the Geleenbeek, one of the three most important stream valleys of South Limburg.