  We extend our model of chemical evolution that successfully account for the
main observables in the solar neighborhood (Alibes, Labay & Canal 2001) to the
whole Milky Way halo and disk. We assume an inside-out scenario for the
assembling of the Galaxy through the infall of external material. Two different
compositions of the infalling material have been considered: primordial and
slightly metal-enriched (0.1 Z_{\sun}). Our calculations follow the evolution
of 76 isotopes up to the Iron peak, but we only present here results for the
elements having well-measured gradients: C, N, O, Ne, Mg, Al, Si, S, Ar and Fe.
The calculated current radial distributions of these elements are compared with
large samples of data from HII regions, B stars, planetary nebulae and open
clusters. We also discuss the time evolution of the abundance gradients. Good
fits are achieved with both infall compositions, closer to the observational
data in the case of primordial infall. We show that contributions from
intermediate-mass stars allow to reproduce the measured abundances of C and N,
but the profiles of their ratios to oxygen leave still open the nucleosynthetic
origin of these elements. In agreement with several previous works, our models
predict a flattening with time of the abundance gradients, most of which taking
place during the early galactic evolution.
