We report about a joint project of the universities at Karlsruhe, Kiel and Ulm on how to get correct compilers for realistic programming languages. Arguing about compiler correctness must strat from a compiling specification describing the correspondence of source and target language in formal terms. We have chosen to use abstract state machines to formalize this correspondence. This allows us to stay with traditional compiler architectures for subdividing the compiler tast. A main achievement is the use of program checking for replacing large parts of compiler verification by the much simpler task of verifying program checkers.