The Current River and its principal tributary, Jacks Fork, are the Ozark National Scenic Riverway's primary natural features. About 60 percent of the baseflow in the two streams is derived from the seven largest springs in the basin. The springs are supplied by diffuse contributions from the regional aquifer system and discrete inflows from sinkholes and losing streams, some of which are outside the Current River basin. Because the streams and springs are the primary attractions to the park, preservation of the physical, chemical, and biological quality and aesthetic appeal of the waters is important. From April 1973 to May 1975, water samples were collected from 19 wells, 7 large springs, 14 sites on the Current River, 7 sites on the Jacks Fork, and 5 tributaries to the Current River and Jacks Fork. Calcium, magnesium, and bicarbonate composed more than 90 percent of the total ionic composition of dissolved material in springs and streams and more than 95 percent in ground water, reflecting the dolomitic composition of the rocks. Dissolved-solids concentrations averaged 276 mg/L (milligrams per liter) in ground water and less than 200 mg/L in springs and streams. Total nitrate concentrations as N averaged 0.22 mg/L in ground water, 0.42 mg/L in springs, and less than 0.65 mg/L in streams. Minor element concentrations were generally low, but on one occasion anomalously high concentrations of total barium, lead, silver, and zinc were found in Blue Spring and the four stream-index stations. The only pesticides detected were 0.03 ?g/L (micrograms per liter) of 2,4-D, and 0.03 ?g/L of 2,4,5-T, and these were in the Current River below Montauk State Park during storm runoff. The streams were relatively free of sediment, except during periods of storm runoff. Fecal coliform and fecal streptococcus densities as high as 2,000 and 2,100 col/100 ml (colonies per 100 milliliters), respectively, were measured in the Jacks Fork downstream from horseback riding activities. Fecal coliform and fecal streptococcus densities of about 4,000 and 22,000 co11100 ml, respectively, were measured in the Current River during storm runoff. Otherwise, bacteria densities averaged less than 100 col/100 ml for fecal coliforms and 200 col/100 ml for fecal streptococci and appear to be relatively unaffected by swimming, camping, canoeing, and other recreational activities in and along streams. The aquatic biota in the Current River and Jacks Fork indicate that the streams generally are unaffected by pollution.