Fish and macroinvertebrate assemblage composition, instream habitat features and surrounding land use were assessed in an agriculturally developed watershed, to relate overall biotic condition to patterns of land use and channel structure. Six sites were sampled on each of three first-order warmwater tributaries located in the morainal section of the watershed. Six fish species accounted for 75% of some 3000 individuals that were collected using a backpack shocking unit. However, fish species richness and Index of Biotic Integrity (IBI) scores varied considerably among sites due to the presence of rare species that accounted for 14 of the 28 species collected. Composite samples of 300 macroinvertebrates were collected at each site with a D-frame net and described with several diversity indices. More differences in relative abundance of taxa were found among sites for macroinvertebrates than for fish. The presence of sensitive taxonomic groups (Ephemeroptera and Trichoptera), which was highly correlated to taxa richness, explained the greatest amount of the variation in the two multimetric macroinvertebrate indices. Analysis of land cover using a Geographical Information System (GIS) showed that agriculture and forest were the dominant land covers within the catchments of each tributary, as well as within 250 m and 100 m buffer regions along each stream. Quantitative and qualitative measures of instream habitat structure varied greatly among the sites. Few significant correlations were found between instream habitat variables and land use, but the tributary with the highest percentage of forest cover in its catchment had greater channel and flow stability, better overall habitat condition, and the highest fish and macroinvertebrate index scores. However, only land use within the 100 m buffer showed significant relationships to biotic measures. Forest cover and agricultural land use within the 100 m buffer explained about 30% of the variation in fish biotic integrity, four of the macroinvertebrate assemblage measures, and habitat quality. Multiple linear regression analysis showed that flow stability (for both fish and macroinvertebrates) and substrate condition (for macroinvertebrates only) explained more of the variation in index scores among sites than did land use/cover alone. This finding suggests that the effects of immediately adjacent land use and fine scale habitat variation are not independen t. This study supports previous results from studies in this watershed indicating that forest cover is positively related to biotic integrity, but contradicts the previous finding that catchment land use explained the greatest amount of variation in fish biotic integrity and habitat quality. T he minor contribution of overall land use to the biotic integrity of the three tributaries may be attributable to the fact that a smaller and more homogeneous geographic area was assess in this study, and indicates that the areal scale of the sampling des ign may determine which scales of land use measurement will show significant relationships.