The synthesis and characterization of a series of novel thermoplastic elastometers, (AB)(n) multiblock copolymers, containing polyisobutylene as the soft phase and polyamides as the hard phase are described. First, carboxyl ditelechelic polyisobutylene prepolymers and isocyanate ditelechelic polyisobutylene prepolymers were synthesized, both of which were subsequently reacted under solution polycondensation conditions with dicarboxylic acids and diisocyanates (see eqs 1 and 2). Molecular weights and molecular weight distributions were determined by GPC and light scattering on trifluoroacetylated samples. The melting points of the polyamide hard phases were in the 223-284 degrees C range. The decomposition temperatures (296-337 degrees C) in air and nitrogen of these TPEs made by eq 1 were quite similar; in contrast, these properties of polytetrahydrofuran-based TPEs were noticeably lower in air. Melt processing of these novel PIB-based TPEs is possible.