Over the years, urban rivers have suffered from environmental degradation due to anthropogenic activities, becoming a public concern. Thus, the objective of this study was to evaluate the spatiotemporal evolution of water quality in the Apodi-Mossor & oacute; River, in the urban section of Mossor & oacute;-RN, during the dry and rainy seasons. To this end, the physical-chemical and microbiological attributes of water samples collected at six points along the urban stretch of the Apodi-Mossor & oacute; River were characterized. Using the water quality data, the Water Quality Index was calculated, and multivariate statistical analysis was performed. The Water Quality Index varied considerably. At the Gen & eacute;sio Dam, a more positive assessment was observed, with ratings ranging from excellent to good. However, the other points showed significant variations, especially the Barrocas Dam, which received all ratings. The attributes that most influenced the results were total Kjeldahl nitrogen, turbidity and biochemical oxygen demand. The river water showed a high salt content, resulting in a classification as brackish at all points evaluated for most of the year, except during the rainy season, when it was considered fresh.