Mails have been missing because of use of invalid postal codes; people have been denied services because they could not submit valid zip or postal codes; jobs have been lost because of want of postal or zip codes. In this information communication technology (ICT) age, virtually no person-to-person, distant business transaction can be carried out without post or zip codes. As we all know, goods can not be delivered through internet or intranets but through our contact addresses or shipping addresses, these addresses are tracked through postal codes. This booklet deals solely with international postal/zip codes. Some countries have, some do not use while some have changed their postal/zip codes over the years whereas some use moire than one. However, this compilation is just an updated list some countries' old code that is no more in use has been discarded in this compilation. Those who still use both their old codes with their new ones have both codes listed in this booklet."