Two national mechanisms regulate the humane treatment of the 20-40 million laboratory animals that are used annually for experimental purposes in the United States each year. They are: the Public Health Service policy (commonly called the National Institutes of Health (NIH) policy) of 1985, and the Animal Welfare Act of 1966 as amended, a federal law. National policies are constantly being strengthened. Until 1984, national policies covered mainly animal husbandry practices. But the 1985 revised NIH policy directly involves the laboratory for the first time by requiring protocol review for humane concerns. Protocol review of proposed experiments is to be conducted by Animal Care and Use Committees--the institutional oversight committees. It is with effective protocol review that the Refinement, Reduction, and Replacement (of Russell and Burch's three Rs) to reduce ethical costs of experiments can be made an everyday reality. With this new authority for Animal Care and Use Committees, and a mandate for broader representation in membership, the revised NIH policy should bring improvements. Proposals are currently being considered by the U.S. Congress to strengthen the Animal Welfare Act. This law is in need of revision since about 90% of the laboratory animals are currently excluded from its coverage. The Scientists Center for Animal Welfare has been active in identifying ways in which national policies can be strengthened. In particular, focus has been made on meaningful protocol review by institutional oversight committees. Some recommendations for effective oversight committees based on recent workshops conducted by the Scientists Center for Animal Welfare are described.