CAS REGISTRYSM Aids Research to Advance Science, Improve Lives.

The CAS REGISTRY database is the most comprehensive collection of disclosed chemical substance information in the world. Recognized as the "gold standard" for substance information, CAS REGISTRY contains more than 92 million unique organic and inorganic substances, such as alloys, coordination compounds, minerals, mixtures, polymers, and salts, and more than 65 million sequences. Research collected in REGISTRY covers a comprehensive range of scientific disciplines, including biomedical sciences, chemistry, engineering, materials science, agricultural science, and many others.

CAS REGISTRY is comprised of scientific data from a variety of reputable sources, including patents, journals, chemical catalogs, and selected online resources dating from 1957 to the present, with additional substances going back to the early 1900s. CAS REGISTRY is updated daily, with more than 15,000 new substances being added each day.

Research Applications

CAS REGISTRY is accessed daily by scientists and researchers around the globe from a variety of industries. Possible applications include:

  • Cancer research: Data contained in CAS REGISTRY enables researchers to gain a greater understanding of the biology of cancer, including its causes and potential cures.
  • Consumer goods: Insight about plastics and metals contained in CAS REGISTRY helps manufacturers of consumer products continue to develop new and innovative product features, more biodegradable plastics, or stronger coatings for vehicles.
  • Patent research: CAS REGISTRY contains comprehensive information about patented discoveries, helping researchers to recognize prior art and avoid wasting time and money on already-patented discoveries.
  • Pharmaceutical discovery: Substance and reaction data contained in CAS REGISTRY helps pharmaceutical researchers make more informed decisions and develop more targeted drugs. Patent data in REGISTRY is also updated daily, helping drug researchers track innovation by their competitors.
  • Technological innovation: Knowledge about semiconductors contained in CAS REGISTRY enables electronics manufacturers to continue to make computers and cell phones faster and smaller.


Top Fortune 500 corporations, more than 2,200 universities, and all major patent offices use CAS products to access CAS REGISTRY for the comprehensive, current, reliable data they need to enable scientific discovery. REGISTRY is accessed by tens of thousands of users around the world.

The insight contained in CAS REGISTRY is available to scientists through SciFinder, CAS' award-winning search product, and its STN family of products. The 7,900 most commonly referenced substances are also available through Common Chemistry, a free, web-based resource produced in collaboration with Wikipedia.


William A. Noyes founded the CAS organization in 1907 to help scientists benefit from the published work of their colleagues around the world by monitoring, abstracting, and indexing the world's chemistry-related literature. The results were printed in Chemical Abstracts (CA).

Over the decades, CAS databases have reflected the progress of science, and its search services have been continually improved to help research scientists and information professionals find and use this information to best advantage. CAS revolutionized the scientific discovery process in 1995 by providing researchers direct access to its databases through the introduction of SciFinder. Today, scientists are only seconds from information needed to conduct research through CAS products delivered over the web and through software applications.

Registration Process

Hundreds of CAS scientists using state-of-the-art technology developed by CAS follow rigorous criteria and consistent guidelines to analyze and index publicly disclosed scientific information to maintain the high quality and reliability of information in CAS REGISTRY. Staff members collectively analyze literature published in more than 180 countries in any of 50 languages.

CAS scientists add value to the data they collect by entering chemical names, a unique CAS Registry Number, and vital literature references into CAS REGISTRY, as well as ancillary information such as experimental and predicted property data (boiling and melting points, etc.), commercial availability, preparation details, spectra, and regulatory information from international sources.

CAS Registry Numbers

Each substance in CAS REGISTRY is assigned a CAS Registry Number®, a unique identifier for chemical substances. A CAS Registry Number provides an unambiguous way to identify a chemical substance or molecular structure when there are many possible systematic, generic, proprietary, or trivial names. Sample CAS Registry Numbers include:

Visit for free access to 7,900 chemical substances and Registry Numbers.