The utilization of irrigation waters in Kansas has increased dramatically since the drought period of the 1950's. With this development has come the need for information which can be used in the determination of compatability of groundwater with soils and crops and in the management of groundwater systems tapped for agricultural purposes. An important component of this information is the chemical character of the waters under consideration. The chemical quality data contained in this report show that groundwater presently in use from the Arkansas River Valley in Kearny, Hamilton, and Finney Counties and a band north of the river in Finney County is of sufficiently poor quality that it could produce adverse effects upon soils and crop yields with uncontroled long term usage. In most cases, poorer quality groundwater is associated with the presence of saline soils and shallow water tables.