The liquidus lines of solid-liquid equilibria for the binary systems 2-heptanone, 3-heptanone, and 4-heptanone with benzene, cyclohexane, and ethanol were determined by means of the visual method. Furthermore enthalpies of fusion of the isomeric heptanones were measured with a Tian-Calvet calorimeter. The experimental SLE data were compared with those calculated from the modified UNIFAC (Dortmund) group contribution method.