We conducted an ichthyofaunal bioassessment on the upper Cahaba River in north central Alabama during the fall of 1995, the spring and fall of 1996, and the spring of 1997. There were trends denoting a loss of habitat stability in areas impacted by anthropogenic sources of pollution, particularly siltation. Negative longitudinal trends were recorded for the index of biotic integrity, sum of studentized residuals (after linear regression of various metrics on drainage area), and the Jaccard index. Several species of cyprinids and percids, which are sensitive to anthropogenic disturbances, are becoming less abundant in the system. We conclude that these changes are related to point and non-point sources of pollution from metropolitan Birmingham.