Linscott's Directory of Immunological & Biological Reagents - Find the antibodies you need right here: Linscott's Directory is a fast, free and easy-to-use resource for locating specific antibodies from nearly 300 commercial and governmental sources. They have over 415,000 antibody listings, which can be searched by keyword, antigen, application, host, reactivity or conjugate. The Directory also lists sources for thousands of proteins, assay kits, custom services, and much more.

AntibodyLink.org - an antibody search portal which connects catalog antibodies and research publications to the UniProt protein information resource. The tool uses a proprietary Antibody Name Dictionary model - a collection of protein names, synonyms, and symbols recognized as antibody names which are verified through a full-text search of scientific publications in HighWire Press.

Antikoerper Online and Antibodies Online and Anticorps-Enligne- A website (in German, English, and French, respectively) that facilitates the search for commerically available antibodies. There are more than 115,000 monoclonal and polyclonal antibodies listed in their database and once found, antibodies can be ordered through the website.

Biocompare - Lists of antibodies, antibody-affinity media, and antibody production services can be found here. Click here to be taken to their interesting antibody specific search tool where you can limit your query by reactivity, host species, isotype, and conjugate type.

BIOgate - an Israeli life science portal with a search engine to find Israeli antibody suppliers

Bionity - among other life science portals one can find an antibody database containing more than 110,000 antibodies from 35 manufacturers

BioSupplyNet - an on-line buyer's guide for researchers. Search by keyword entry.

ExactAntigen - a site that trolls thousands of websites - mainly from commercial suppliers - and other sources to locate providers of antibodies (and other reagents). Users can search by categories such as gene, organism, and disease. The results often list antibody products along with publications and relevant patents.

IHC Mall - self described as "The Buyer's Guide For Histology Professionals" - search and find antibodies alphabetically or by research areas. There are 120,000+ antibodies and immunological related reagents in their database.

There are major antibody suppliers that will search for an antibody if they do not have what you are looking for in their own catalog.  Examples of such services include the Novus Antibody Concierge and the AbD Serotec AntibodyDetective Service.