Water quality information associated with peanut (Arachis hypogea L.) culture is limited, but needed from both environmental and agronomic standpoints. In this study, we consider surface and ground water quality characteristics involved with conventional till (viz, moldboard plow) culture of irrigated peanuts. During a 3- and a 6-year study, sediment and associated nitrogen (N) and phosphorus (P) discharge in surface water runoff were measured from two similarly managed peanut watersheds in southwestern Oklahoma. Mean annual discharge from the Cobb fine sandy loam soil (Udic Haplustalf with 2% slope) was approximately 20 Mg ha^-1 sediment, 18 kg ha^-1 total N, and 5 kg ha^-1 total P. Annual soluble N and P losses in surface water runoff tended to be small (< 1 kg ha^-1). Even so, concentrations of soluble P in runoff frequently exceeded recommended eutrophication guidelines. Successful prediction of soluble P, particulate P, and particulate N losses was achieved using appropriate kinetic desorption and enrichment ratio techniques. Concentrations of N and P in the watersheds' ground waters posed no particular water quality problems. Sampling for pesticides associated with peanut culture was made during the middle and at the end of the study, but none were detected in surface or ground waters. Overall, additional attention should be directed to reducing soil erosion. This may be done by judicious use of cover crops, and/or reduced tillage practices.