Abstract: Aqueous fluids for circulation through a well during drilling operations, especially drilling operations where shale and another clay bearing formations are encountered, and methods for circulating such clay stabilizing drilling fluids are provided for. The drilling fluid comprises an aqueous base fluid, a viscosifying polymer, a starch, and a chloride-free clay stabilizer. In one embodiment, the starch is selected from the group consisting of potato and corn starch and mixtures thereof and is present in relatively high amounts, i.e., starch in amounts from about 6 to about 18 lb/barrel of fluid, and stabilizer in amounts up to about 3% by volume of fluid. Other embodiments provide concentrations of polymer, starch, and clay stabilizer effective to provide the fluid with clay swelling of about 10% or less, preferably about 5% or less, and shale disintegration of about 10% or less, preferably about 5% or less. Preferably the novel fluids also comprise an environmentally friendly lubricant and surfactant.