This paper reviews synthetis, molecular structure, properties, performance and application of cardo polymers which contain at least one element in the repeating unit that is included in the cyclic side group. The properties of cardo polymers depend on the backbone structure. The presence of cardo groups in different hetero- and carbochain polymers endows them with very specific properties: enhanced thermal stability together with excellent solubility, which is of particular importance in aromatic heterocyclic polymers with rigid chains. This survey covers synthesis, properties and applications of the following cardo polymers - aromatic polyesters, aromatic polyamides, polyimides, poly-1,3,4-oxadiazoles, polycarbonates, polyarylates, aromatic polyimides, and cardo carbochain polymers. Extensive chemistry and property data are tabulated.