Abstract: The rough sets theory proves to be a very useful tool for analysis of information tables which describes objects by means of disjoint subsets of condition and decision attributes The key idea of rough sets is approximation of knowledge expressed by decision attributes using knowledge expressed by condition attributes In real life the decision and condition concepts are often fuzzy and described by fuzzy sets A new method for decision making is proposed, which is derived from the combination of rough sets and fuzzy sets The concept of inclusion degree of fuzzy sets and level approximation and aggregation function are given, and discussing the relationship between condition and decision attributes with some examples This offers theoretical foundation for assigning the weights to condition attributes during decision making