In 2009 and 2010, drift samples were collected from six sites on the lower Sprague and Williamson Rivers to assess drift patterns of larval Lost River suckers (Deltistes luxatus) (LRS) and shortnose suckers (Chasmistes brevirostris) (SNS). The objective of this study was to characterize the drift timing, relative abundance, and growth stage frequencies of larval suckers emigrating from the Sprague River watershed. These data were used to evaluate changes in spawning distribution of LRS and SNS in the Sprague River after the 2008 removal of Chiloquin Dam. Drift samples were collected at four sites on the Sprague River and one site each on the Williamson and Sycan Rivers.