Intrusion detection systems have been around for quite some time, to protect systems from inside ad outside threats. Researchers and scientists are concerned on how to enhance the intrusion detection performance, to be able to deal with real-time attacks and detect them fast from quick response. One way to improve performance is to use minimal number of features to de?ne a model in a way that it can be used to accurately discriminate normal from anomalous behaviour. Many feature selection techniques are out there to reduce feature sets or extract new features out of them. In this paper, we propose an anomaly detectors generation approach using genetic algorithm in conjunction with several features selection techniques, including principle components analysis, sequential ?oating, and correlation-based feature selection. A Genetic algorithm was applied with deterministic crowding niching technique, to generate a set of detectors from a single run. The results show that sequential-?oating techniques with the genetic algorithm have the best results, compared to others tested, especially the sequential ?oating forward selection with detection accuracy 92.86% on the train set and 85.38% on the test set.