Rabbit corneal endothelial intracellular pH and electrical potential difference were measured using radioactive tracer techniques. A variety of drugs and chemicals were used to modify specific aspects of cell membranes in order to determine, in this steady state system, whether a close relationship existed between intracellular pH and potential. Corneal swelling and deswelling rates were also determined in the presence and absence of the drugs. Longer times of immersion of tissue with drugs (3 hours) tended to provide more support for a link between intracellular pH and the inability of the cornea to maintain a constant thickness. Drugs that altered corneal thickness without altering either intracellular pH or potential difference presumably acted on extracellular pathways. No conclusive evidence was obtained for a direct link between intracellular pH and the intracellular electrical potential difference of the endothelial cell.