Abstract Continuous casting (CC) belongs to the metallurgical technologies which during last forty years radically charged nature of steel production. It denotes revolution in steel casting technology. First and foremost it eliminated heavy operations, introduced smoothness to the steel production and allowed considerable increase of earnings as effect of energy and manufacturing cast savings. The intensive development in 80. and 90. years of last century was oriented on increasing of cast volumes, casting speed, complexity of the process, its automation and achieving of high firmness and safety of operation and also on increasing of surface and inner quality of cast products. At the same time many knowledge and experience were achieved, which leads to the fact, that CC is today high effective dominating technology for production of quality steel products. The dominant part is further process online by metals forming technologies. In the paper theoretical analyse of present state is performed in the field of cracking theory of CC steel products. There is analyse of fundamentals of seven theories and hypothesis of cracking, which were showed in literature: crystallizing cracking, creep failure, embrittlement induced by copper weared from crystalliser, cracking associated with oscillation marks, cracking associated with creation of local heat nodes, precipitation induced embrittlement and embrittlement in austenite – ferrite phase area. These theories are basis at interpreting creating mechanics of surface cracks on CC products.