Doctor Zoidburg said:
I have a tennant who paid the rent late for four months, I took him to court and he lost the case. Does this effect his credit rating in the future?
(The judgement was that he had to pay on the agreed date.)
Given the facts you provide Dr. Zoidburg, where I am
no, a landlord-tenant case such as this would
not affect his credit rating - after all he did pay albeit late and the court ruling was merely ‘in the future pay on time’. If, however, he had failed to pay several months rent, and you obtained a judgement against him for amount of the unpaid rent then you could (presumably in Ontario as well) report that judgement to the credit bureaus (however, you would be well advised to make sure that he had exhausted any appeals before doing so).
As usual you are well advised to check with a Lawyer in your area face to face before you take any action.