We report on the search for single top production in $e^+e^-$
collisions, using the data corresponding to an integrated luminosity 
of 626 pb$^{-1}$ collected by L3 at a centre of mass energy between 
189 and 207 GeV. We present two independent analyses in the purely 
hadronic and semileptonic top decay channels. No evidence of
single top production at LEP2 is obtained. Combining the results 
of both analyses, we quote the 95\% confidence level upper limits on 
single top cross sections for $\sqrt{s}$ in the range 189-207 GeV.