Common carp is one of the oldest cultured and most domesticated fish in the world, and is a very adaptable species in both the wild and in culture coditions. The genetic resources of common carp maintained at the Fish Culture Research Institute in Szarvas, Hungary, are described in this paper. The genetic improvement of common carp in Hungary started in 1962. Five main features were evaluated that determined the economic value of the resulting strains: survival, weight gain, feed conversion ratio, slaughter value and fat content of the meat. The Fish Culture Research Institute plays a key role in a national breeding programme in Hungary that provides fish farms and fish seed production units with parental lines of hybrid common carp.