The ARGO-YBJ detector at the YangBaJing Cosmic Ray Observatory (4300 m a.s.l., Tibet, P.R. China) has been put into operation in the full configration since November 2007. It is the first EAS detector combining a very high mountain altitude with a full coverage detection surface. The high time-space granularity combined with the full coverage make ARGO-YBJ a unique device to study the EAS characteristics. In this paper we report a few selected results in Gamma-Ray Astronomy and Cosmic Ray Physics