Fault-tolerance in integrated circuit design has become an alarming issue for circuit designers and semiconductor industries wishing to downscale transistor dimensions to their utmost. The motivation to conduct research on fault-tolerant design is backed by the observation that the noise which was ineffective in the large-dimension circuits is expected to cause a significant downgraded performance in low-scaled transistor operation of future CMOS technology models. This paper is destined to give an overview of all the major fault-tolerance techniques and noise models proposed so far. Summing and analysing all this work, we have divided the literature into three categories and discussed their applicability in terms of proposing circuit design modifications, finding output error probability or methods proposed to achieve highly accurate simulation results. © 2010 IEEE.