Nowadays, there are plenty of approaches to determine steroids hormones by capillary electrophoresis, however, the development of new ones is still actual. In the present study, the possibilities of 3-methyl-1-β-cyclodextrinimidazole tosylate as pseudo stationary phase are considered. Due to the formation of positively charged complexes between steroids with a derivative based on β-cyclodextrin and imidazolium cation, the following results were achieved: first, it was established that adding of this modifier at concentration 0.70 mM at pH 3.2 allowed to separate the five most important corticosteroid hormones (cortisone, hydrocortisone, 11-deoxycortisol, corticosterone, 21-hydroxyprogesterone). Second, the presence of a modifier in the sample permitted to carry out electrokinetic injection of samples and preconcentration of analytes under field-amplified sample injection mode. Obtained values of limits of detection (5–15 ng/cm ³) allowed to analyze plasma samples after liquid–liquid extraction by chloroform. Graphic abstract: [Figure not available: see fulltext.]