Thermoplastic elastomers are disclosed which are prepared by; (I) mixing, (A) a thermoplastic resin comprising more than 50 percent by volume of a polyamide or a polyester resin, (B) a silicone base comprising; (B') 100 parts by weight of a diorganopolysiloxane gum having a plasticity of at least 30 and having an average of at least 2 alkenyl groups per molecule and (B") 5 to 200 parts by weight of a reinforcing filler, wherein the weight ratio of said silicone base to said polyamide or polyester resin is from 35:65 to 85:15, (C) a compatibilizer, (D) a radical initiator, present in an amount sufficient to cure said diorganopolysiloxane gum, and optionally (E) a stabilizer, (II) dynamically vulcanizing said diorganopolysiloxanes gum, wherein at least one property of the thermoplastic elastomer selected from tensile strength or elongation is at least 25% greater than the respective property for a corresponding simple blend wherein said diorganopolysiloxane is not cured and said thermoplastic elastomer has an elongation of at least 25%.