Water quality in various aquatic ecosystems has become very important nowadays due to the effects of anthropogenic impact, which is why developed countries have made managements plans for these ecosystems based mostly on the use of physicochemical indices that provide instantaneous data on the state of the resource and, according to these indices, establish regulations on the management of this resource. Therefore, at present the use of bioindicators has become very relevant when evaluating aquatic ecosystems, since they can evaluate not only the quality in physicochemical terms but also the ecological quality of the entire ecosystem. In this sense, the research aimed to evaluate the water quality of the Toribio River using macroinvertebrates as bioindicators, applying the BMWP -Biological Monitoring Working Party- biological index. The study was descriptive since physicochemical data and the different populations of macroinvertebrates present in three stations established in the lower area of the Toribio River were collected in two rainy seasons of the year: one rainy and the other dry. For this, specimen capture, identification and taxonomic classification were carried out to later apply the BMWP index, in order to establish the ecological quality of the ecosystem. Among the data obtained from the sampling, one of the most notable is the difference in macroinvertebrates present in the two seasons studied (dry season and rainy seasons) and how these conditions affect the presence or absence of these species.