A methodology for Patient Costing is presented, which is based upon a division of nursing care into Direct, Indirect and a residual category, and which is consistent with costing methods recommended by the Audit Commission. The system was used to produce patient costs upon 14 wards in Wales. The results show wide differences in costs, both between and within wards. Many patients used few nursing resources, and a quarter cost less than £13.00 for the two day shifts. This study was commissioned by the Welsh Office