Some organizations may also wish to be a registered charity. One of the main reasons to do so is the ability to offer tax receipts to donors. You do not need to be incorporated to be registered as a charity, but that is the common practice in non-profits.
Charity Central has compiled a resource book on the process and requirements. Please refer to this booklet for the complete information on registration with the Canada Revenue Agency (CRA).
Charity Central Guideline to CRA