We made the chemical analysis of several RR Lyrae stars which presumably 
are ex-Omega Cen members. Selection process was based on objects kinematics. 
Spectral data were obtained from UVES spectrograph at the ESO VLT and from 
SARG spectrograph at the TNG with high resolution (R ~ 30000) in the range 
4000-8500 A. The spectra were used to unequivocally identify ex-Omega Cen 
members: we derived highly accurate elemental abundances, to confirm or 
disprove the extragalactic origin of this stellar system.
We will show the results of chemical and radial velocity analysis of RR Lyrae 
on all points of pulsation cycle and make first assumptions about the origin 
of Omega Cen system.