Jeff, did you try pop_select? That should do the trick, I think. EEG = pop_select(EEG,'time',[begin_ms end_ms]) cheers, jan -- Jan R. Wessel Cognitive Neurology Max Planck Institute for Neurological Research Gleueler Strasse 50, 50931 Koeln http://www.nf.mpg.de/cv/jan-wessel.html