How to Get an ISMN
If you wish to obtain an ISMN publisher ID, you should contact your country's or region's national ISMN agency. The local ISMN representative will give you further information on the procedure of the ISMN assignment. This may differ from country to country, as do regulations concerning fees and charges.
The number of digits which your ISMN publisher ID will include should reflect the size of your company, i.e. smaller publishing houses should receive a long publisher ID (for example, seven digits allowing only ten publications to be numbered), larger publishing houses will receive a short publisher ID (for example, three digits allowing 100,000 publications to be numbered).
Author publishers are also entitled to an ISMN.
Presently, about 60 countries or regions are official ISMN members. The contact addresses of all national agencies are listed here.