Being an executor and beneficiary of a will is very common and there is no law in Alberta that disallows it. Often, people are both the executor and sole beneficiary of the estate. You will see this when the spouse of the deceased person is appointed executor in the will and inherits the entire estate. In other situations, one of the deceased's children is appointed executor and is also one of the beneficiaries.
If you are the executor and beneficiary of a will, and there are other beneficiaries, you may want to have one estate lawyer representing you as the executor and another representing you as the beneficiary. This will help avoid the perception of there being a conflict of interest. Whether they are beneficiaries or not, executors have a legal duty to act in the best interests of all the beneficiaries and treat everyone equally and fairly.
It's important to remember that you are only the executor if you have been named as such in a will. If the deceased person did not leave a will, he or she is considered intestate. In this case, you may have to apply to the court for a Grant of Administration to give you the power to administer the estate.
A Grant of Administration is not always required. It is only required if the intestate estate would have had to go through probate had their been a will. The grant issued by the court provides legal proof that you are allowed to manage and distribute the estate.
As a side note, when you are creating a will, do not allow one of your beneficiaries or their spouses to be a witness. If you do, the witness and/or the spouse will not be allowed to receive anything left to him or her in the will. Gifts to beneficiaries or their spouses who act as witnesses become invalid while the will remains valid.