The chi(1)-interaction parameters of poly(dimethyl siloxane) with methyl ethyl ketone at very low polymer concentration were determined by means of intrinsic viscosity (IV) measurements at several temperatures. The chi(t)(infinity)-total interaction parameters of the same system at infinitely high polymer concentration were also determined using inverse gas chromatography (i.g.c.) technique around the same temperature range. Then, exchange enthalpy, X-12, and entropy, Q(12), parameters in the Flory’s equation of state theory were determined from the obtained interaction parameters. Both X-12 and Q(12) parameters obtained by TV are lower than those found by i.g.c..