ISIC is the abbreviation for International Standard Industrial Classification of All Economic Activities whereas SIC is the abbreviation for
Standard Industrial Classification. - Both are completely different classification systems, and although comparable at certain levels, are entirely independent from one another. SIC Codes predate ISIC codes and were developed by and for the United States. The ISIC Code system is developed and updated by the United Nations and many countries throughout the world rely on it for their industrial classifications. For business targeting purposes in the United States and Canada, the SIC Code system is the preferred and most precise method available.