A proof of claim is the form document a creditor must complete to be paid from the assets of a bankruptcy case. The proof of claim generally tells the bankruptcy trustee whether the claim is secured or unsecured, priority or nonpriority, and the amount of the claim. All creditors who want to be paid from the bankruptcy estate must file a proof of claim in Chapter 7, 12, and 13 bankruptcy cases—except in Chapter 7 no-asset cases, as there are no funds for distribution to creditors.

In Massachusetts, as in all states, a proof of claim is a formal statement that creditors must file to assert their right to receive payment from a debtor's bankruptcy estate. This document is required in Chapter 7 (liquidation), Chapter 12 (adjustment of debts of a family farmer or fisherman), and Chapter 13 (individual debt adjustment) bankruptcy cases, provided there are assets available to distribute. The proof of claim form must detail whether the debt is secured or unsecured, whether it holds priority status, and the claim's total amount. Creditors must submit this form to the bankruptcy court by a specified deadline, which is typically 90 days after the first date set for the meeting of creditors in a Chapter 7 asset case and Chapter 13 case, and in a Chapter 12 case, the deadline is typically 90 days after the order for relief. However, in Chapter 7 no-asset cases, creditors are not required to file a proof of claim because there are no assets to distribute. The bankruptcy trustee uses the information provided in the proof of claim to determine how to distribute the bankruptcy estate's assets. Failure to file a proof of claim may result in the creditor not being paid. It is important for creditors to be aware of the specific deadlines and requirements for filing a proof of claim in the relevant bankruptcy chapter and to ensure that the information provided is accurate and complete.