Interannual-to-decadal predictability of the Paran¿ river in South America is investigated by extracting near-cyclic components in summer-season streamflows at Corrientes over the period 1904--1997. It is found that oscillatory components with periods of about 2--5, 8 and 17 years are accompanied by statistically significant changes in monthly streamflow. Autoregressive predictive models are constructed for each component. Cross-validated categorical hindcasts based on the 8-yr predicted component are found to yield some skill up to four years in advance for below-average flows. A prediction based upon the 8- and 17-yr components including data up to 1999 suggests increased probability of below-average flows until 2006. ¿ 2001 American Geophysical Union