Visit the Canada Revenue Agency website as well as related sites here.
As a contractor/consultant, it is important for you to determine whether you are considered an employee or self-employed in your working relationships from the perspective of the CRA. In each case, your entitlements are different. Most of the time, the degree of control over the work you perform is a determining factor in deciding whether you are an employee or self-employed.
If you are uncertain, review the specific conditions to determine your employment relationship by taking a look at the following publication: