Sulfate uptake into skin fibroblasts from patients with cystic fibrosis is increased. Sulfate transport studies were carried out in skin fibroblasts isolated from age/sex matched cystic fibrosis and normal subjects. Sulfate transport occurred mainly via a carrier-mediated proton-stimulated SO42/Cl-exchange. The capacity (Vmax) of the uptake system operating at physiological concentrations of sulfate was stimulated in cystic fibrosis, but the affinity of the carrier for sulfate was not altered. © 1988 Academic Press, Inc.