Phorbol-12, 13-dibutyrate, epidermal growth factor, and insulin raised the intracellular pH ( [pH]i), presumably through the activation of a Na⁺/H⁺ antiporter. Addition of amiloride or replacement of extracellular Na⁺ by choline which abolishes the cytoplasmic alkalinization prevented the stimulation of hexose transport by these agents. Furthermore, monensin, a Na⁺/H⁺ ionophore which increases the [pH]i, stimulated hexose transport. This stimulation was also prevented by the replacement of extracellular Na+ by choline. These observations suggest that stimulation of the Na+/11+ antiporter may have stimulated the increase in hexose transport.