In a business where a database tracks customers and manages customer accounts, a method and system correctly link accounts with customers. The method entails reading customer information for a first customer and for a second customer, and then utilizing personal identification information obtained from other sources to determine if the first customer is the same as the second customer. If the first customer and the second customer are the same person, the first customer and the second customer are identified as being the same unique person. Accounts associated with the two customers are identified as belonging to the same unique person. Viewed another way, the method and system of the present invention takes an existing database of personal identification information, and cross-references that database against other sources of personal identification information to identify persons who appear to be separate persons, but who are actually one and the same individual.