This report presents the twelfth annual report of the Council for Scientific and Industrial Research. The report covers the period from the 17th August, 1956, the date on which the Standards (Transfer of Administration) Act of 1956 came into force, to 31st March, 1957, which coincides with the end of the Council’s financial year. In addition to the fields of research covered in the previous annual reports, this report includes sections dealing with the activities of the South African Bureau of Standards. Balance sheets and statements of income and expenditure for the financial year ended 31st March, 1957, certified by the Controller and Auditor-General, are also presented.