Río Ichilo is a Bolivian river at the foot of the Eastern Andes-Cordillera in South America. Río Ichilo has its source in Manuel Maria Caballero Province in Santa Cruz Department at an elevation of 2,437 m at the foothills of Serranía Racete, where it has the name of "Alto Ichilo" (Upper Ichilo).

In its course, after joining Río San Matéo, it is called Ichilo, flowing in a northerly direction, where it forms the border between Cochabamba Department and Santa Cruz Department.

From its source to the mouth into the Amazon the river has a total length of 2,455 km. Ichilo itself has a length of 632 km and a catchment area of 15,660 km². It has its maximum depth is 18.6 m, right below Puerto Villarroel at km 100, its maximum width is 420 m at km 75. Ichilo is one of the Bolivian rivers with a high amount of water. The most important tributaries of the Ichilo are the Bolivian Río Grande, Chapare, Piraí, Sacta, Víbora, Chimoré, Choré, Ibaresito, Ibabo and Useuta. Río Ichilo passes the metropolitan aerea of Santa Cruz in the west, the largest cities on the riverbanks is Puerto Villaroel.