Technical Abstract: Flue gas desulfurization (FGD)-gypsum production has increased 44 percent from 2007 to 2008. The major use of FGD-gypsum today is in the wallboard industry. Reduction in the construction, however, reduces the demand for wallboard. Agriculture could become the second largest user of FGD-gypsum. FGD-gypsum and used wallboard from FGD non-FGD-gypsum could be use in agriculture. FGD-gypsum has been shown to be effective as calcium and sulfur fertilizer and as a neutralizing agent for acidic and sodic soils. It has been reported that gypsum and calcium sulfate will influence root growth in soybean. Therefore, the objective of this study was to compare root length of corn and soybean grown in sand media amended with FGD-gypsum, used non-FGD-gypsum wallboard and reagent grade calcium sulfate. The materials were mixed with sand at the rate of 280, 560 and 1120 kg ha-1 and placed 16 ounce plastic cups. Plants were grown for 14 days. Total root length was determined using a root counter instrument. Root lengths for corn were 327± 43, 283 ± 49, 272 ± 28 and 235 ± 62 cm for calcium sulfate, FGD-gypsum, used non-FGD-wallboard gypsum and control respectively, while the root length for soybean were, 274 ±73, 282 ± 54, 279 ± 62 and 299 ± 23 calcium sulfate, FGD-gypsum, used non-FGD-wallboard gypsum and control respectively. Only for soybean, root length decreased with increasing treatment rates.