Wetlands are the cradle of biological diversity and provide the water and primary productivity on which countless plant and animal species depend for their survival. The identification of the stand structure constituting this biodiversity makes it possible to assess the status of this biodiversity and the quality of these ecological and economic functions produces wetlands. In this sense, we have carried out surveys of the macroinvertebrate fauna of Oued R'dom, a tributary of Oued Sebou which is one of the main rivers in Morocco. The results show that at the wadi R'dom level the population groups 43 species divided into 43 genera, 33 families, 6 classes and many Orders. All the inventoried fauna belongs to 3 systematic branches: Arthropods, Molluscs and Annelids. However, 75% of the inventoried species belong to the class of Insects. In addition, the overall distribution of species varies from one systematic taxon to another and with in each taxon. It should be noted that the identification of the macroinvertebrate population is of great importance in the constitution of certain biotic indices, such as the Globalised General Biological Index (GGBI), which is used as a tool for assessing the biological quality of the environment. It should be noted that the identification of the macroinvertebrate population is of great importance in the constitution of certain biotic indices, such as the Globalised General Biological Index (GGBI), which is used as a tool for assessing the biological quality of the environment.