We present the results from a high-resolution optical spectroscopic survey aimed to search 
for  nearby young associations and young stars among optical counterparts of ROSAT All-Sky 
Survey X-ray sources in the Southern Hemisphere. We selected 1953 late-type 
($B-V~\geq~0.6$), potentially young, optical counterparts out of a total of 9574 1RXS 
sources for follow-up observations. At least one high-resolution spectrum was obtained for 
about 1800 targets. 
We describe a convergence method in the (UVW) velocity space to find associations and we 
present the nearby young associations detected by this method on the SACY sample.