When buying a real estate investment (Toronto, ON) are the mortgage payment tax

[Toronto_Student_AB]

I have been thinking for a while about buying a house as an investment.
Lately I have found this house, divided to several units, and rented out.
The asking price is low enough for the mortgage payments to be lower than its revenue.
If it was that easy I am guessing every one would do it, so what is the catch?
Thanks
Thanks guys for your help.
I understand the rational that not every Canadian can carry another mortgage, but most can.
The problem however arises from the fact that the principal portion of the mortgage payment is not tax deductible, so at the end of the year I will have to pay taxes over revenue that I did not pocket, and paid as mortgage payments. This is THE CATCH that makes it not affordable.
Thanks for your answers!

[Worldly25]

Only the interest.  Principle is your responsibility

[hanora]

The catch is that you have to have the money to buy it.  The lender (if it is a major Canadian bank) is going to want at least 30% down and they are not going to include all the potential rent in your financial statement.  So unless you can comfortably carry this mortgage in addition to your other bills they are going to be skittish.

It's not easy, tenants don't always pay rent.  The law favours tenants a bit, it can take months to get rid of a bad tenant and there is little recourse.  Sure you can go to small claims, but what to they care?  If you get a bad tenant that knows the rules it can take more than 6 months to get rid of them.

Multiple units?  Oh my word!  These are almost all illegal unless they were built as such, meaning that they don't meet code.  Toronto blinks at them, but your insurer won't and if you have a mortgage you will need insurance.

However to answer your question.  You can deduct the interest, the property tax, any utilities you provide.  If you have to replace the furnace, roof, ect. that's a capital cost and your accountant can tell your about the depreciation rate.