Suspended solids and algal populations were characterized in 16 south central Oklahoma lakes to relate their properties to the spectral reflectances recorded by satellites. The average concentrations of natural suspended solids in the lakes ranged from 7 to 190 g/m3. Ash content increased from about 65 to 90 percent as suspended solids concentrations increased. Mean particle diameter, determined by photon correlation spectroscopy on samples with more than 40 g/m3of suspended solids, ranged from 400 to 2,000 nm. Nutrient concentrations were low; dissolved inorganic nitrogen was less than 0.4 g/m3, and water-soluble phosphorus was less than 25 mg/m3. Algal populations were also low, with chlorophyllaconcentrations averaging 6 mg/m3and rarely exceeding 20 mg/m3. Reflectances in the satellite spectral bands varied only slightly in response to changes in visual color and particle size of suspended solids in the turbid lakes. The relatively low chlorophyll concentrations could not be detected in the satellite spectral bands.