Hypertext/text domains are characterized by several tens or hundreds of thousands of features. This represents a challenge for supervised learning algorithms which have to learn accurate classifiers using a small set of available training examples. In this paper, a fuzzy semi-supervised support vector machines (FSS-SVM) algorithm is proposed. It tries to overcome the need for a large labelled training set. For this, it uses both labelled and unlabelled data for training. It also modulates the effect of the unlabelled data in the learning process. Empirical evaluations with two real-world hypertext datasets showed that, by additionally using unlabelled data, FSS-SVM requires less labelled training data than its supervised version, support vector machines, to achieve the same level of classification performance. Also, the incorporated fuzzy membership values of the unlabelled training patterns in the learning process have positively influenced the classification performance in comparison with its crisp variant.