The miscibilities of acetone and deuterated acetone with decane, tridecane, hexadecane, octadecane and eicosane over a broad concentration range have been determined. All the measured systems present phase diagrams with a visible asymmetry with respect to composition and are characterized by the upper critical solution temperature (UCST). It appears that deuterium substitution in acetone leads to the significant upward shift of UCST, increasing the domain of the limited miscibility. The phase diagrams were described by using a scaling equation with a critical exponent P close to the theoretically predicted one and practically independent of isotope substitution and hydrocarbon chain length. (C) 2003 Elsevier B.V. All rights reserved.