The Mississippi Department of Revenue has found mistakes in 36,000 homestead exemption filings.
MDR officials said that it found cases where people were paying too little, too much or, in most instances, enjoying the tax break a deceased elderly or disabled relative formerly received.
MDR officials credit the discovery of the problems to new computer software employed to determine which Mississippi residents qualify for a homestead exemption tax break.
Under homestead exemption, the state encourages people to own homes by exempting the houses from some property taxes.
The state reimburses counties and cities for lost tax revenues from homestead exemption.
Those reimbursements, local officials say, have not kept pace with actual losses experienced by cities and counties.