Descripción: “...Este estudio demuestra la opción de reducir la contaminación por materia orgánica utilizando humedales construidos.Abstract: Constructed wetlands appear at the present time like a promising technology in reducing the pollution by waste waters; this study investigated the organic matter removal with synthetic waste water, in terms of chemical oxygen demand (COD), biological oxygen demand (BOD5) and in situ measurements of pH, oxygen and temperature every 15 days, during three months, in six horizontal subsurface-flow constructed wetland systems, in pilot scale, seeded with three different macrophytes: Canna limbata, Heliconia psittacorum and Phragmites sp; the average removals of COD were of 97,31 % and 95,94 % for Canna limbata; 94,49 % and 93,50 % for Heliconia psittacorum; 97,39 % and 97,13 % for Phragmites sp. ...”