In general you should not issue an official donation receipt for a conditional gift unless you are sure that the condition will be fulfilled. If in doubt best to wait till the condition is fulfilled and then to issue the receipt.

Summary Policy
Date
September 3, 2003 (Revised November 23, 2005)
Reference Number
CSP – G04
Key Words
Gift (conditional)
Policy Statement
There are two types of conditions that can be attached to a gift: a condition precedent, and a condition subsequent.

A condition precedent is one that must be met before the gift takes effect (e.g., a gift of $100,000 provided that the registered charity is able to raise an equal amount of money within a stated period of time). Since a condition precedent is not a gift at law until after the condition is fulfilled, a charity should only issue an official donation receipt after the condition has been met.

A condition subsequent is one that operates to defeat a gift that has already been made (e.g., a gift made to a registered charity on the condition that the funds be used to operate a particular shelter for the homeless). If a condition subsequent fails and the gift reverts back to the donor, the charity should advise the Canada Revenue Agency that the original gift is being returned to the donor. A condition subsequent may result in a subsequent tax liability.
References
• Gift (donation), CSP-G01.
• Receipt, CSP-R02.