Asynchronous circuits have recently been a breakthrough in many high performance computers. The concept of asynchronous circuits which started a long time ago has slowly grasped the attention of many designers. The Muller-C-element is an important control block in many asynchronous designs and therefore it is important to understand some of the possible failures that might occur in this circuit. The timing and behavior of this element will have an important effect on the overall performance of the system. The purpose of this research is to study some of the common failures that exist in synchronous logic and find out if these failures can also happen in the C-element. Condition for a failure must be present in order for it to occur. Understanding the conditions required for a circuit failure to occur, we will show realistic examples in the applications of C-element in which such similar conditions will also happen. In this thesis, we are interested in analyzing the circuit failures in C-element due to different logic threshold voltages of different devices, problem of charge-sharing and metastabilty characteristic of circuit. Simulations results will show such failures does occur in the C-element when the conditions were met. / Graduation date: 1997