In this paper, a methodology for generating VHDL descriptions of hardware checkers is presented. It is shown how the methodology can be used to generate on-line checkers of communication protocols, counters, decoders, registers, comparators, etc. It is also demonstrated how a checker for more complex structures can be developed. We describe the possibilities of utilizing this approach in the design of Fault Tolerant Systems (FTS). Experimental results in terms of FPGA resources needed to synthesize different types of checkers are presented.