Isobaric liquid-liquid equilibrium (LLE) data were determined at atmospheric pressure and at 293 K for limonene + water and citral + water binary systems (solubility data) as well as for water + ethanol + citral and water + ethanol + limonene ternary systems (tie lines and miscibility gaps). Ethanol enhances the mutual solubility between water and citral and between water and limonene. The miscibility gap disappears for an ethanol mass fraction equal to about 0.45 for the first system and about 0.73 for the second one. The binary and ternary experimental data were fitted by means of the UNIQUAC model. New and previously unavailable UNIQUAC interaction parameters were determined. The quality of the fit is good. © 1995, American Chemical Society. All rights reserved.