Create a document, heading it "Disclaimer." IRS rules require that you prepare and execute this document within nine months of the death of the person who made the bequest. If you miss the deadline, the property automatically becomes a personal asset for income tax purposes.
Complete the disclaimer by using language to the effect that you are unconditionally disclaiming property bequeathed to you in a will. Identify the will by date and author; identify the property by address and/or legal property identification number. You may not direct ownership to another person; by law, the contingent beneficiary will gain ownership.
Sign and date the disclaimer. You may not execute a disclaimer before the death of the testator -- the person who wrote the will. In addition, you may disclaim a portion, and not all, of an inheritance. Have the disclaimer witnessed and notarized by a notary public, who is authorized by law to witness your signature.
File the disclaimer in the local court handling the probate case, if the estate is going through probate, and send it to the executor of the estate via certified mail. If the property was bequeathed to you in a trust, and the estate is avoiding probate, send the disclaimer to the trustee via certified mail. The trustee is the individual handling the estate and the bequests; he has the responsibility to oversee the transfer of assets to the beneficiaries.