Systems and methods for classifying e-mail messages as spam by combining outputs of a plurality of spam classifiers or classification tools using a fuzzy logic voting algorithm or formula are provided. According to one embodiment, a first classification value associated with an e-mail message and a second classification value associated with the e-mail message are received. The first classification value and the second classification value being indicative of whether the e-mail message is spam. Then, a single, aggregated classification value for the e-mail message is generated by combining the first classification value and the second classification value using a fuzzy logic-based voting mechanism.