Samples of water, fish, and benthic macroinvertebrates collected at 10 sampling stations over a 10-month period indicate that Sacony Creek and its major tributaries possess water of good to excellent quality. No excessive quantities of dissolved nutrients, oxidizable matter, or fecal coliform bacteria were detected. Fish inhabitants include a sizable wild trout population in the upper Sacony basin and a diverse warm-water population, dominated by white suckers (Catostomus commersoni), in the lower basin. A population of 590 trout or 119 pounds per acre (133 kilograms per square hectometer) was estimated for good habitat in the upper basin. A maximum standing crop of 558 pounds per acre (626 kilograms per square hectometer) was measured at' one of the more productive reaches. Benthic macroinvertebrate collections tended to support the water chemistry and fish population studies. Diversity (d) and Redundancy (r) ranged from 2.44 to 3.46 and 0.14 to 0.38, respectively. Such diversity and redundancy values indicate good quality water at all stations.