Using high-resolution non radiative SPH simulations we study the scaling laws of galaxy clusters. In particular, we analyze the relations existing between total mass, gas temperature, X-ray luminosity and dark matter velocity dispersion. Our aim is to understand how these scaling laws depend on numerical, statistical and physical parameters, in order to model and thus reduce potential systematical uncertainties. The simulations were performed by the GADGET code in a $\Lambda CDM$ cosmology, applying resimulation techniques; their mass resolution ranges between $2 \times 10^9$ and $6.8 \times 10^9 h^{-1}M_{\odot}$ for dark matter particles and between $3 \times 10^8$ and $7 \times 10^8 h^{-1}M_{\odot}$ for gas particles.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html