Room temperature ionic liquids (RTIL) are organic salts composed of an organic cation and organic or inorganic anion, with a melting point below room temperature. They have been used as novel solvent systems in organic synthesis, solvents immiscible with water and polar solvents in liquid-liquid extraction, new background electrolytes for voltammetric studies and batteries, non-volatile matrices for MALDI-MS, stationary phases in gas chromatography and mobile phases in HPLC. In this study, RTILs were used as stationary phases in capillary gas chromatography. Kovats retention indexes of model mixtures of hydroformylating products of undec-1-ene, dodec-1-ene and tridec-1-ene, were measured. The measured data were confronted with those on classical (commercial) nonpolar column HP-5 (5 % poly(diphenylsiloxane) – 95 % poly(dimethyl¬siloxane)) and polar column SP-2340 (100 % poly[bis(3-cyanopropyl)siloxane]).