1. The monomers used in addition polymerisation contain at least one carbon-carbon double bonds in each molecule while the monomers used in condensation polymerisation contain functional groups at both ends of its molecular structure.

2. Addition polymerisation produces only a single product, the addition polymer while condensation polymerisation produces two products, the condensation polymer and a small molecule, usually water.

3. The empirical formula of the addition polymer is the same as the empirical formula of the monomer while the empirical formula of the condensation polymer is different from the empirical formula of the monomer(s).

4. In addition polymerisation, there is no loss of atoms from the monomers during the polymerisation process. In condensation polymerisation, there is loss of atoms from the monomers during the polymerisation process.