  The ARGO--YBJ experiment has been in stable data taking for more than five
years at the Yangbajing cosmic ray observatory (Tibet, P.R. China, 4300 m
a.s.l.). The detector collected about $5\times10^{11}$ events in a wide energy
range from few TeVs up to the PeV region. In this work we summarize the latest
results in cosmic ray physics particularly focusing on the cosmic ray energy
spectrum. The results of the measurement of the all-particle and proton plus
helium energy spectra in the energy region between $10^{12} - 10^{16}$ eV are
discussed. A precise measurement of the cosmic ray energy spectrum and
composition in this energy region allows a better understanding of the origin
of the knee and provides a powerful cross-check among different experimental
techniques.
