Southern Alberta has the highest density of feedlot cattle in Canada. However, the quantity and quality of runoff from beef cattle fedlots in this region has not been investigated. Our objective was to compare runoff quantity (1998-2002) to catch-basin design criteria; determine concentrations of selected inorganic chemical parameters (1998-2000) in runoff in relation to water quality guidelines and the potential implications of irrigating adjacent cropland; and determine if total heterotrophs, total coliforms, and Escherichia coli (1998-2000) persisted in the catch-basin water and soil. Runoff (< 0.1 to 42.5 mm) of 24-h duration that included maximum peak discharge was less than the recommended design criteria of 90 mm based on runoff from 24-h rainfall with 30-yr return period. We found that curve numbers between 52 and 96 (mode of 90) were required to match the USDA Natural Resources Conservation Service predicted runoff and actual runoff volumes. Total P posed the greatest threat to water quality guidelines, and K posed the greatest threat for exceeding crop fertilizer requirements if catch-basin effluent was used as irrigation water. Water in the catch basin had continually high populations of E. coli throughout the study. In contrast, soil in the catch basin generally had low populations of E. coli, but at times higher populations were also found.