Nutrient and suspended-sediment samples were collected in calendar year 1999 during baseflow and stormflow from the Susquehanna River at Towanda, Danville, and Marietta, the West Branch Susquehanna River at Lewisburg, the Juniata River at Newport, and the Conestoga River at Conestoga, Pennsylvania. Annual loads of nutrients and suspended sediment were highest in the Susquehanna River at Marietta, followed by the Susquehanna River at Danville. The Conestoga River at Conestoga had the smallest load, in pounds per year, but had the greatest yield, in pounds per acre per year, of total nitrogen, total phosphorus and suspended sediment. Seasonal loads of nutrients and suspended sediment generally varied according to the variations in the seasonal water discharges. Comparison of the 1999 yields and the fiveyear baseline yields indicates that total nitrogen loads decreased at all of the monitoring sites. Total phosphorus loads decreased at four sites. Suspended-sediment loads increased at one site, decreased at another, and remained the same at three sites. and flow-adjusted concentration. The results showed improving conditions in total nitrogen and total phosphorus throughout the Susquehanna River Basin. Improving conditions in suspended sediment occurred at three of the six stations in the basin. Trends were computed for the period January 1985 to December 1999 for total and dissolved nitrogen, total and dissolved organic nitrogen, total and dissolved ammonia, total and dissolved kjeldahl nitrogen, total and dissolved nitrite plus nitrate, total phosphorus and dissolved phosphorus, dissolved inorganic phosphorus, total organic carbon, suspended sediment and flow. River at Conestoga, Pennsylvania. Results were reported for monthly mean flow, monthly load, monthly flow-weighted concentration, and flow-adjusted concentration. The results showed improving conditions in total nitrogen and total phosphorus throughout the Susquehanna River Basin. Improving conditions in suspended sediment occurred at three of the six stations in the basin.