The first need of State Machines is that many electronic systems require the type of sequential operation exhibited by state machines. Therefore, state machine design can be applied to the solution of a wide variety of practical circuit problems. Secondly state machine design methods lead to minimal design. In combinational circuits we found that the Karnaugh map was useful in minimizing the number of gates required to implement a logic function. Although the importance of this tool has perhaps diminished as a result of the availability of MUXs, PLAs, ROMs, and decoders, it remains a significant method in combinational design. The state machine design procedure plays the same role in sequential circuits that of the K-map in combinational circuits.The design results in the minimum number of flip-flops and minimisese other security in the system as well. The last is that it is a well-developed, orderly procedure that anticipates and solves commonly occurring problems of sequential circuits. Other design procedures often result in the appearance of very narrow unwanted pulses or glitches on output lines or occasional oscillation problems. State machine methods are required to eliminate these problems and reduces the time taken to debug the implemented hardware.