In Fall 2001, Indiana University Southeast Ecology students conducted darter population and bioassessment studies at three established sites on Blue River, a southern Indiana tributary of the Ohio River. Using a Zippin removal depletion method, we collected 205 riffle fishes representing 11 species. Greenside and rainbow darters outnumbered spotted darters for the first time. Extremely low numbers of bluebreast darters may be related to alteration of White Cloud dam and destruction of Rothrock’s dam. Macroinvertebrate assessment values increased at all three sites and may be related to improved efficiency at the Salem sewage treatment plant. Habitat assessments indicate Blue River is very close to a pristine river system.Major problems are associated with increasing recreational use, drought, watershed development and storm discharge with elevated bacteria, turbidity and nutrients.Water quality is within acceptable limits except during storm discharge periods. Future studies should consider a riffle resource partitioning study, sedimentation monitoring, periphyton analyses, and water quality analyses during peak discharge periods.