Normal function was simulated in nonfunctioning heart and bladder of dogs by implanting ferromagnetic material on or in the walls of these organs and applying a magnetic field to produce compression against the body wall. A field of 0.1 T and a 0.05‐T/cm gradient applied to three strips of C1010 steel (each 8.5 g and 5.1×2.5×0.08 cm), sutured to the base of the right ventricle of the 165‐g heart of a 17.5‐kg dog, produced normal left and right intraventricular pressures. At higher field gradients, less metal was needed. A magnetic field of 0.17 T and 0.11 T/cm applied to a steel strip of 0.22 g, or to 0.48 g of sintered iron on or in the posterior wall of the bladder of a 19‐kg dog containing 75‐cc saline produced a rise in intravesical pressure of up to 16 mm Hg, adequate for complete emptying. The forces produced by application of high magnetic fields to ferromagnetic material on or in dog heart or bladder appeared to be sufficient to restore function in man.