This paper extends a series of experiments performed by Schonlau et al. [1] on the detection of computer masqueraders (i.e. illegitimate users trying to impersonate legitimate ones). A compression-based classication algorithm called Normalized Compression Distance or NCD, developed by Vitányi et al. [2] is applied on the same data set. It is shown that the NCD-based approach performs as well as the methods previously tried by Schonlau et al. Future work, possible enhancements and directions of further research on this topic are presented as well.Sociedad Argentina de Informática e Investigación Operativa