CD-modified microemulsion EKC as a CE technique has been applied to the chiral separation of atropine, scopolamine, ipratropium and homatropine. Enantioseparations of these tropa alkaloids were optimized by using a standard oil-in-water (O/W) microemulsion and varying the nature and concentration of CD additives as well as of the organic modifier (methanol, 2-propanol or ACN) whilst keeping the applied voltage of 15 kV and capillary temperature of 30 degrees C constant. The standard (O/W) microemulsion BGE solution consisted of 0.8% w/w octane, 6.6% w/w 1-butanol, 2.0% w/w SDS and 90.6% w/w 10 mM sodium tetraborate buffer (pH 9.2). Enantioseparations with high resolution and short migration times of all tropa alkaloids were achieved by using heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-CD and sulfated beta-CD in the microemulsion BGE and were superior to corresponding CD-modified CE methods.