We report the possible aggregation of phosphate and ionic liquid (1-tetradecyl-3-methylimidazolium chloride) based BGEs during MEKC. After a certain transit period, the aggregates appear as a random sequence of spikes on a UV detector signal. Root mean square values of the spikes and aggregation time (T-a) were plotted against BGE concentrations. The observation suggests that MEKC is a simple and easy technique for micelle aggregation studies.