The swamp complexes of the Momposina depression in the lower Magdalena River have been submitted to irrational exploitation, transformation and contamination mainly since the beginning of the century, process that has been getting worse in the last decade. The most evident manifestation of the environmental deterioration is expressed by the drastic reduction of fishing, with important socio-economic effects to the population that lives from this source.The most notorious causes of the actual state of the ecosystem were detected, and some preliminary considerations for its management are presented. However, due to the modifications that the complexes have suffered (closure of the natural sewer, construction of jarillones, modifications of the internal water flows and sediments, overexploitation of fish and herpetofauna), the deterioration of the limnologyc conditions is moderated, which allows to begin recuperation plans. The major impacts were observed in the fauna of birds and reptiles associated to the swamps; the decrease of the icticas populations seems to be related to the strong impact generated by the fishing action used and the interruption of the natural cycles of fish. The possibility of rebuilding the communication swamp-river, should be studied with care because it seems the system has arrived to new conditions. The re-opening of the sewers could mean a new unbalanced condition represented mainly by the contamination coming from the Magdalena River.