Application of the Transvarestraint test to assessment of solidification cracking susceptibility of overlay welds made by MAG method on S355JR steel has been presented. A specific test rig enabling to apply different strain of the test piece with high speed was designed. In the course of the research the weld pool temperature history was registered, cracking qualification was done and the examination of crack opening and HAZ using scanning electron microscopy and light microscopy was carried out. Solidification cracking temperature range of this material system was determined.