The subject of the invention is a delayed-action thermal relay especially suitable for starting motors for refrigerator compressors and the like comprising a housing molded of plastic material with a first, a second, and a third electric terminal molded into the housing, a first U-shaped bimetallic strip inserted between the first and third electrical terminals and carrying in intermediate position at the base portion of the U-shape a contact element cooperating in normally closed condition with a corresponding contact element carried by a second bimetallic strip connected to the second electrical terminal. There is provided on said respective bimetallic strips associated permanent magnet and armature means which tend to keep said bimetallic strips and hence the contact elements provided on the strips electrically engaged in a closed circuit position.