Canada has strict laws regarding criminal inadmissibility. If you wish to enter Canada permanently or temporarily, you may be denied entry if you or your dependents are deemed criminally inadmissible. Even a drunk driving charge, for example, can prevent you from entering Canada.
However, if you are criminally inadmissible but are otherwise qualified to enter Canada, you may be allowed to enter if you are deemed rehabilitated by an immigration officer or you apply for individual rehabilitation.
You may be deemed rehabilitated depending on the seriousness of your crime and how much time has elapsed since the completion of your sentence. You may be eligible to apply for individual rehabilitation if 5 years have passed since the completion of your sentence.