While there have been many public discussions concerning Medicare covering outpatient prescription medications, currently, Medicare does not pay for most outpatient prescriptions. Meanwhile, costs associated with prescription medications as well as the number of underinsured patients are rapidly increasing. Many pharmaceutical companies offer assistance programs for patients who require medications but have inadequate financial resources to obtain them. Because patient access to required prescriptions is critical and clinician involvement is necessary for patient enrollment, the purpose of this article is to facilitate awareness of pharmaceutical companies' assistance programs, the availability of such programs, and their enrollment process.English-language articles from MEDLINE (1963-2000) and Internet Web pages describing medication assistance programs were reviewed. Data obtained from pharmaceutical companies' medication assistance programs were also included. In addition to general information concerning medication assistance programs, all studies found in the literature search describing the clinical and financial impact of using these programs and data obtained from contacting several medication assistance programs were selected. To determine if an assistance program was available for a medication listed as one of the top 200 medications prescribed in the United States, we contacted the pharmaceutical company that manufactures each medication.Approximately 53% of the top 200 prescribed medications in 1999 were offered through assistance programs to indigent patients. Physician office personnel can obtain medications for eligible patients by completing the enrollment process.Pharmaceutical companies' medication assistance programs can be used to reduce individual patient drug expenditures and improve patient outcomes by increasing medication access to those in need.