We propose to study the evolution of ZF-muSR and low-field (100 G) TF-muSR spectra and relaxation times across the charge ordering temperature T0 = 140 K of RbFe2As2 iron based superconductor. The experiments will be performed on a high quality sample which have been already characterized by XRD, 87,85Rb and 75As NMR-NQR, SQUID magnetometry and ac susceptibility. The muSR measurements, together with NQR measurements and single crystal 75As NMR measurements, will provide a complete microscopic characterization of the charge order allowing us to better understand the nature of that phase.