Use of a standard prescription pad, although it adequately meets the needs of drug delivery, requires the physician to document prescribed medications separately in the medical record. Failure to do so may lead to under-recognition of problems of potential drug interactions and adverse drug reactions, delays in prescription refills, and other areas of quality of care, especially in a setting where multiple physicians may be involved in the care of a patient. Of 83 prescriptions written in a primary care clinic, only 11 (13%) were noted on the chart medication form when physicians used prescription pads. Implementation of a "one-write" noncarbon prescription form that generated an instant copy increased prescription documentation to 83% (49 of 59 prescriptions) (x2 = 68.86; p < 0.005) over a one-week period. In a follow-up study conducted approximately 3.5 years after the initial intervention, use of the "one-write" form had maintained at 82% prescription documentation (32 of 39) prescriptions) (x2 = 52.05; p < 0.005). A "one-write" copy system could improve clinical care by improving medication documentation in the medical record.