The development of a commercial‐scale sputtering process for deposition of superconducitng YBa2Cu3O7(YBCO) thin films is described.YBCO films are sputter deposited from a single 20 cm diameter powder target onto 2 inch substrates of MgO and LaAlO3usingin‐situheating to produce high quality, c‐axis oriented films without post annealing. By locating the substrate above the center of the magnetron erosion ring and by placing a ‘‘negative ion shield’’ between the target and the substrate, negative ion resputtering is avoided. Small shifts in composition are corrected by using a slightly Y‐ and Cu‐rich target to produce films within 1% of stoichiometric composition. Films on LaAlO3and MgO have critical temperatures up to 88 K and critical currents above 5×105A/cm2at 77 K. Uniformity is ±5% in thickness and ±7% in resistivity across at 2‐inch diameter substrate. Microwave surface resistance meaurements at 1.2 GHz and 4 K showRS≊0.1 m&OHgr; for YBCO ground planes and ≊0.3 m&OHgr; for patterned YBCO striplines on MgO.