Polymerization process including polymerizing a monomer and a comonomer in a polymerization reaction, withdrawing an effluent stream containing solid polymer and a mixture of unreacted monomer and unreacted comonomer, and passing the effluent to a high pressure recovery system having (a) a high pressure separation step for separating vapor containing unreacted monomer and unreacted comonomer from the solids, and (b) a high pressure recycle system for recycling a portion of the vapor to the polymerization reaction, passing the solids from the high pressure recovery system to a low pressure recovery system having (a) a low pressure separation step for separating further unreacted monomer and unreacted comonomer from the solids, and (b) a low pressure recycle system for recycling at least a portion of the unreacted monomer and unreacted comonomer to the polymerization reaction. A portion of the vapor separated in step 2(a) is passed to the low pressure recovery system.