Abstract. We say that there is an association between two sets of items when the sets are likely to occur together in transactions. In information retrieval, an association between two keyword sets means that they co-occur in a record or document. In databases, an association is a rule latent in the databases whereby an attribute set can be inferred from another.Generally, the number of associations may be large, so we look for those that are particularly strong. Maximal association rules were introduced by [3,4], and there is only one maximal association.Rough set theory has been used successfully for data mining. By using this theory, rules that are similar to maximal associations can be found. However, we show that the rough set approach to discovering knowledge is much simpler than the maximal association method.