The pressure-volume-temperature (P-V-T) properties of a number of metallocene-produced polyolefins were measured experimentally at 10 MPa less than or equal to P less than or equal to 200 MPa and 30 degrees C less than or equal to T less than or equal to 220 degrees C in a dilatometer-type P-V-T apparatus. These included ethylene copolymers typical of linear low density polyethylene, with several alpha-olefins as comonomers and a wide range of comonomer content. The experimental P-V-T data were correlated with the equations of state from the Sanchez-Lacombe and Flory-Orwoll-Vrij theories. The solubility parameter map of the polyolefins, at atmospheric pressure, was established on the basis of the thermodynamic data. As the temperature increases, the solubility parameter of the polyolefin decreases. The solubility parameters of copolymers of ethylene with :propylene, butene, hexene, and octene under constant temperature are all more or less the same at equal weight percent of comonomer. As the incorporation of branches increases, the solubility parameter decreases. The melt miscibility of the polyolefin blends can be predicted to design various blend products for specific applications from this solubility parameter map.