Seismic activity of Mt. Etna volcano has been investigated by analysing time-spatial fractal dimensions and the b value of the Gutenberg-Richter's law relatively to two differing eruptive style periods, i.e. 1983–1988 and 1993–1996. The obtained results evidence two different volcano stress conditions before and after the large intrusive episode occurred during the time span 1989–1992. Fractal dimensions and the b value seem to be a promising tool to understand the internal current state of the volcano, allowing to evaluate the short-middle term volcanic hazard.