Provided are a method, system, and article of manufacture for using a data mining algorithm to discover data rules. A data set including multiple records is processed to generate data rules for the data set. Each record has a record format including a plurality of fields and each rule provides a predicted condition for one field based on at least one predictor condition in at least one other field. The generated data rules are provided to a user interface to enable a user to edit the generated data rules. The data rules are stored in a rule repository to be available to use to validate data sets having the record format.