Are bad debts that are written off taxable or not?

"Written off" does not always (usually) mean a debt is not still collectible. The term "forgiven" indicates that the creditor no longer considers the debt valid. When a debt is forgiven the debtor will receive a 1099C from the creditor/collector and a copy is sent to the IRS.. The debt is then considered income and must be reported on the debtor's tax return as such.