The instrument PAMELA, in orbit since 15 June 2006 on board of the Russian satellite Resurs DK1, is de- signed to study charged particles in the cosmic radiation, with a particular focus on antimatter and signals of dark mat- ter annihilation. PAMELA is also looking for primordial antinuclei, measuring light nuclei energy spectra, studying the mechanisms of acceleration and propagation of the cos- mic rays in the Galaxy, and monitoring the solar activity and the radiation belts. A review of the main experimental results obtained by PAMELA is presented in this paper. The observed anoma- lous positron excess is discussed in terms of annihilation of dark matter particles as well as in terms of standard astro- physical sources. Moreover constraints on dark matter mod- els from antiproton data are shown.