The phase behavior of cationic surfactant/oil/water/alcohol systems was systematically scanned to correlate the attainment of three-phase microemulsion-oil-water systems with the following formulation variables: water phase salinity as sodium chloride concentration, oil alkane carbon number (CAN) or equivalent ACN when the oil phase is not an alkane, surfactant alkyl chain length, surfactant hydrophilic group (both amine salts at acid pH and quaternary ammonium compounds at neutral pH), alcohol and temperature effects.