When you buy a new or used residential property in Toronto, you are obliged to pay Municipal and Provincial Land Transfer Tax upon closing. These taxes will be payable when you transfer an interest to someone else be it a sibling or friend.
Recently clients wishing to change the number of the owners from 3 to 2 family members find that they have to pay taxes on 1/3 of the remaining outstanding mortgage
Some exemptions will be:
certain transfers between spouses
certain transfers from an individual to their family business corporation
certain transfers of farmed land between family members
certain transfers of a life lease from a non-profit organization or a charity.
Here is a LTT calculator from the Toronto Real Estate Board http://www.torontorealestateboard.com/buying/LTT_calculator/ltt_calculator.htm
Please check prior to making any final decisions about transfering property.