In this paper we show that the massive parallelism, the synchronous appli-
cation of the rules, and the discrete nature of their computation, among other features,
lead us to consider P systems as natural tools for dealing with fractals. Several examples
of fractals encoded by P systems are presented and we wonder about using P systems as
a new tool for representing and simulating the fractal nature of tumors.Ministerio de Eduación y Ciencia TIN2005-09345-C04-0