espanolSe evaluo la calidad microbiologica del agua de los rios Manaure y Casacara (departamento del Cesar, Colombia) durante la temporada de lluvias y de sequia. Se estimaron las concentraciones de coliformes totales, coliformes fecales, enterococos fecales,Pseudomonas aeruginosa y Salmonella a traves del metodo del Sustrato Definido. Los valores de coliformes totales y coliformes fecales se compararon con la normatividad colombiana (Resolucion 2115 del 2007 y Decretos 1594 del 1984 y 3930 de 2010). Los resultados de los parametros microbiologicos evaluados fueron variables para ambos rios en las dos epocas climaticas, siendo mayores en la temporada de sequia. Se determino que la presencia de las bacterias indicadoras de contaminacion fecal y potencialmente patogenas en los rios estudiados se debe a los vertimientos aledanos de aguas residuales domesticas, agricolas y asentamientos humanos que condicionan la calidad y el uso de recurso hidrico establecido por la normatividad colombiana. EnglishThe microbiological quality of the water of the Manaure and Casacara rivers (department of Cesar, Colombia) was evaluated during the rainy and dry season. The concentrations of total coliforms, fecal coliforms, fecal enterococcus, Pseudomonas aeruginosa and Salmonellawere determined through the Defined Substrate method. The values of total coliforms and fecal coliforms were compared with the Colombian regulations (Resolution 2115 of 2007 and decrees 1594 of 1984 and 3930 of 2010). The results of the microbiological parameters evaluated were variable for both rivers, being higher in the dry season. It was determined that the presence of fecal contamination indicators and potentially pathogenic bacteria in the studied rivers is due to the surrounding discharges of domestic and agricultural wastewater, and to human settlements that condition the quality and use of water resources established by Colombian regulations.